Cam help for TBI 350

[tayto]

Hey guys, I have a project that has basically been sitting for 2 years and only been driven a handful of times since I got it running 3 summers ago. Basically had an engine built 6 years ago, and when I went to install it a few years ago I figured I'd get it dyno'd. While it made decent power (375 FWHP/420 FWTQ) when we went to drain the coolant out of the block we discovered the drains were blocked solid. Tear down was recommended and we found the coolant passages caked with rock hard sediment. I removed a ziplock sandwich bag worth of crap AFTER the new machine shop hot tanked the block! Also found bearing clearances were tighter than normal so ended up getting the block re-rebuilt. I'm not saying the machine shop tricked me, but they definitely didn't give me "good" advice. Had I know how bad the engine had been rebuilt in the first place, I probably would have just walked on the project and just been done with it, but instead I just kept spending. Live and learn. Anyway, this is what I have and hopefully it can be made better so I can get the car tuned and enjoy it.

350 2-bolt block bored .030"
Sealed Power flat top pistons (H345NP) with 5cc valve reliefs
Vortec heads, modified for high lift cam (~.570")
CompCams 07-466-9 (http://www.compcams.com/%28S%28b2gdl5reai1wm245gf0mpe55%29%29/Company/CC/cam-specs/Details.aspx?csid=1110&sb=0) 218/224 @ .050 113* LSA .570/.56
stamped steel 1.6 rockers and stock length pushrods
CompCams BeeHive springs (26918)
stock OEM roller lifters
Edelbrock Performer RPM intake with coolant plumbed to run under TBI (per rbob from DynamicEFI)
454 TBI, with "cop car" injectors running @ 30 psi with VRFPR
Tri-Y headers (1 5/8") and 2 1/2" duals with X pipe, full tail pipes

I personally think the cam is to big for my application (4200 lbs B-body). Another issue I had was not getting proper oiling at idle to all rockers. It seemed the outside corner cylinders would not oil correctly. Not sure if this is lifter, cam or cam bearing related. I have good oil pressure (~40-60 psi @ idle depending temperature) When I first manually primed the engine a few years ago I got good oil flow to all rockers, so maybe it is distributor related as I used a gutted distributor to prime engine... I am very close to just selling the car and getting what I can for it, it does run right now so I am have on the fence about seeing if I can just get it tuned and call it a day. I no longer have a garage or place to work so I would have to rent something to do any more. Any suggestions appreciated.

[Fast355]

Hey guys, I have a project that has basically been sitting for 2 years and only been driven a handful of times since I got it running 3 summers ago. Basically had an engine built 6 years ago, and when I went to install it a few years ago I figured I'd get it dyno'd. While it made decent power (375 FWHP/420 FWTQ) when we went to drain the coolant out of the block we discovered the drains were blocked solid. Tear down was recommended and we found the coolant passages caked with rock hard sediment. I removed a ziplock sandwich bag worth of crap AFTER the new machine shop hot tanked the block! Also found bearing clearances were tighter than normal so ended up getting the block re-rebuilt. I'm not saying the machine shop tricked me, but they definitely didn't give me "good" advice. Had I know how bad the engine had been rebuilt in the first place, I probably would have just walked on the project and just been done with it, but instead I just kept spending. Live and learn. Anyway, this is what I have and hopefully it can be made better so I can get the car tuned and enjoy it.

350 2-bolt block bored .030"
Sealed Power flat top pistons (H345NP) with 5cc valve reliefs
Vortec heads, modified for high lift cam (~.570")
CompCams 07-466-9 (http://www.compcams.com/%28S%28b2gdl5reai1wm245gf0mpe55%29%29/Company/CC/cam-specs/Details.aspx?csid=1110&sb=0) 218/224 @ .050 113* LSA .570/.56
stamped steel 1.6 rockers and stock length pushrods
CompCams BeeHive springs (26918)
stock OEM roller lifters
Edelbrock Performer RPM intake with coolant plumbed to run under TBI (per rbob from DynamicEFI)
454 TBI, with "cop car" injectors running @ 30 psi with VRFPR
Tri-Y headers (1 5/8") and 2 1/2" duals with X pipe, full tail pipes

I personally think the cam is to big for my application (4200 lbs B-body). Another issue I had was not getting proper oiling at idle to all rockers. It seemed the outside corner cylinders would not oil correctly. Not sure if this is lifter, cam or cam bearing related. I have good oil pressure (~40-60 psi @ idle depending temperature) When I first manually primed the engine a few years ago I got good oil flow to all rockers, so maybe it is distributor related as I used a gutted distributor to prime engine... I am very close to just selling the car and getting what I can for it, it does run right now so I am have on the fence about seeing if I can just get it tuned and call it a day. I no longer have a garage or place to work so I would have to rent something to do any more. Any suggestions appreciated.

The cam is not too big with the right combination of compression, intake, exhaust, stall speed and gear ratio. I ran a 232/240* @ .050 roller cam in a 10.5:1 383 with modified SLP TPI setup in my 5,000 lbs G20 van for while. A little sluggish off-idle, but it came on strong through the midrange and screamed on the top-end. I was only running a L35 S10 converter in the 4L60E and 3.08 gears in the rear. I could cruise 80+ mph locked up in overdrive all day long at 2,000 rpm.

I am not a fan of stamped steel rockers, especially with a cam of that lift.

With that setup I would run a 2,600-2,800 rpm stall torque converter and 4.10s to push your heavy beast off the line.

The cam in my 97 Express van is 215/220 @ .050 on a 114* LSA and I am running it on the stock 2,200 rpm 4L80E converter and only have 3.73s in the rear. I have had over 7,000 lbs hanging on the trailer hitch of the ~6,000 lbs conversion van and never felt the cam was "too big".

[tayto]

I am sitting around 10:1 compression, and a quench in the .060" range which is kind of disappointing. What would you recommend for rocker arms? Just the roller tip ones? I do not want to spend $500 on a roller rocker setup. Currently have 3.42s behind a 700R4 that I rebuilt with one of Dana's rebuild kits. I have Edge 9.5" converter that stalls at 2600 rpm. Seriously think I am just going to leave it as is and see if I can find someone to tune it. I don't mind tweaking minour things myself but over the past few years have virtually lost interested in this wanting to learn how to tune and the "car" hobby in general. Any other suggestions Fast would be great, I know you've done lots of TBI setups...

[Fast355]

I am sitting around 10:1 compression, and a quench in the .060" range which is kind of disappointing. What would you recommend for rocker arms? Just the roller tip ones? I do not want to spend $500 on a roller rocker setup. Currently have 3.42s behind a 700R4 that I rebuilt with one of Dana's rebuild kits. I have Edge 9.5" converter that stalls at 2600 rpm. Seriously think I am just going to leave it as is and see if I can find someone to tune it. I don't mind tweaking minour things myself but over the past few years have virtually lost interested in this wanting to learn how to tune and the "car" hobby in general. Any other suggestions Fast would be great, I know you've done lots of TBI setups...

.060" quench is not helping combustion efficiency or detonation resistance at all.

Just the roller tip is a waste of good money IMO. I would go with the comp ultra pro magnum self aligning. The fulcrum is where most of the friction losses occur and the stamped steel rockers deflect under high lift/high spring loading. You said you didn't want a $500 rocker setup, the ProMagnums are $339.00 shipped through Jegs. My old recomendation would have been the Crane Gold narrow body LT4 style rockers, but since Crane relaunched they believe their stuff is made of silver, gold and platinum and pricing reflects it. I like the Pro Magnums because they are steel and will not fatigue as easily as an aluminum rocker.

http://www.jegs.com/i/COMP+Cams/249/1618-16/10002/-1

I am not a fan of Edge converters although I have not run one. I watched a 2,800 Edge that was spec'd by Andre himself slow down a 2003ish Dodge Dakota with a mildly built up 4.7. I also saw a cammed 5.7 Hemi Ram held back by an Edge, switch to an APS with the same stall speed rating and pickup 3 tenths in the 1/8! Depending on the stalll speed in your setup, it may need a restall. Not quite sure Andres logic to use a 9.5" converter for only a 2,600 stall. The factory S10 converter stalls 2,600-2,800 behind a modestly built 350 and only cost $120 remanufactured. Had one in the 99 Suburban with a LT1 cam, cold air intake, headers, dual exhaust and HP Tuners tune. For being a 5,200 lbs truck it had some get up and go!

[Fast355]

As for the cam, you could try degreeing it on a 107* ICL rather than a 109*, this would give you 6* total advance and more off-idle and midrange torque from the earlier valve timing. That being said it will raise your dynamic compression ratio. Another way to gain power across the board would be with a pair of rubber embossed steel shim head gaskets. If you are running a piston that is .025" in the hole, and you use a .016" compressed rubber embossed steel shim head gasket you will be at .041" quench rather than .060". You will gain roughly 1/2 point of compression. With good quench you will have less of a tendency to detonate and the vortec head can work more efficiently in respect to swirl and tumble. If you happened to run into detonation with the higher compression ratio, you could retard the cam to a 113* ICL and lower your dynamic compression ratio some.

[Fast355]

What specifically is wrong with the car that you would think the cam is too big??? Just doesn't have the take-off you would expect? Runs poorly? If it has not been tuned correctly it could be mostly tune. I really don't see any particular mis-match in your combination other than quench. I am not a fan of stamped steel rockers or Edge converters but I doubt they are noticeably hurting your setup, just not much of an improvement over stock parts.

Do you have a .BIN file and datalog for the car? Is this car running the EBL?

[tayto]

Cam has been advanced 4* as per the original builder, so I believe this is already 6* total advance? I thought running over 10:1 on vortec heads was not a good idea unless you're running over 91 octane? anything over 91 in Canada isn't the easiest thing to come by. Currently running 91, noticed a huge decrease in knock counts since going down 2 steps colder on my plugs. Yes running EBL. I think it mainly needs to be tuned, I just don't have the know-how or interest anymore. No one locally seems to want to tune it. I tried Dave at Old school EFI since he is only about a 6 hour drive from me, but it seemed like to hot of a setup for him. BIN and most recent log from this summer attached.

Just a note on my injectors, they are cop car injectors and I got them flowed at witchhunter. I got him to flow them @ 30 psi they came out to 113 lbs/hr, roughly 74 lbs/hr @ 13 psi... Currently running them @ 30 psi and setup the bin accordingly. wondering if this is to high maybe need to drop it down a few psi?

[tayto]

fast, was looking at those rockers. i will have to check the studs in the heads not sure if they are 3/8 or smaller...

[mytmouz]

Stock lifters with that lift cam could be your oiling issue. The oil holes on the side of the lifter body can clear the lifter bore. Comp (and others) sell a lifter specifically to address this...

[tayto]

Yes I have heard of this and is most likely why I am having oiling issues. Crane makes these "long travel" lifters and they are in tune of of $700 for a set. This is one of the reason I was debating going to a smaller (lift wise) cam...

[mytmouz]

Comp cams brand is much cheaper than that...

[tayto]

p/n?

[mytmouz]

OK, reread everything. The long travel lifters you are referring to are for a small base circle camshaft. This keeps them from dropping out of the lifter bore. Comp doesn't offer a cam shaft with a base circle small enough to allow that to happen in the OE hydraulic roller line up. Comp makes 2 lifter sets, a OE style p/n 850-16 same as what you have, and a 'short travel" p/n 875-016. Those are what I went with as recommended by Comps Tech line...

[Fast355]

Cam has been advanced 4* as per the original builder, so I believe this is already 6* total advance? I thought running over 10:1 on vortec heads was not a good idea unless you're running over 91 octane? anything over 91 in Canada isn't the easiest thing to come by. Currently running 91, noticed a huge decrease in knock counts since going down 2 steps colder on my plugs. Yes running EBL. I think it mainly needs to be tuned, I just don't have the know-how or interest anymore. No one locally seems to want to tune it. I tried Dave at Old school EFI since he is only about a 6 hour drive from me, but it seemed like to hot of a setup for him. BIN and most recent log from this summer attached.

Just a note on my injectors, they are cop car injectors and I got them flowed at witchhunter. I got him to flow them @ 30 psi they came out to 113 lbs/hr, roughly 74 lbs/hr @ 13 psi... Currently running them @ 30 psi and setup the bin accordingly. wondering if this is to high maybe need to drop it down a few psi?

I need to dig out my tuning laptop and download these and look at them. Have been sick and haven't felt like messing with it much.

113 lb/hr x2 /.45 x .85 = 426 hp worth of fuel

If you are under 75% duty cycle at WOT you can lower the pressure about 4 psi and see where you end up. Honestly if your injectors are 74# at 13 psi and increase to 113# @ 30 psi they are exactly where the math would show. Math actually shows 112.4 lb/hr. A 68# injector rated at 11 psi should also flow right at 74 lb/hr @ 13 psi.

Now this is where experience and math comes in. The setup you have should be good for about 400 hp. At .45 lb/hr/hp bsfc you need 180 lb/hr of fuel flow. At 85% duty cycle you need 212 lb/hr of fuel flow from the injectors. With 2 injectors, each injector needs to flow 106 lb/hr. With a base flow of 74 lb/hr @ 13 psi and working the pressure formula backwards you need 26.67 psi fuel pressure to support 400 HP. If you end up a little over 85% DC it won't be the end of the world.

[Fast355]

fast, was looking at those rockers. i will have to check the studs in the heads not sure if they are 3/8 or smaller...

If they are still press-in stock studs they are 3/8" on a factory L31 Vortec head.

[Fast355]

Yes I have heard of this and is most likely why I am having oiling issues. Crane makes these "long travel" lifters and they are in tune of of $700 for a set. This is one of the reason I was debating going to a smaller (lift wise) cam...

A set of LS7 lifters from GMPP are roughly 1/6 the cost and would work just as well if an oiling issue due to the lifters existed. Might simply be too much open spring pressure collapsing the weaker stock lifters.

http://www.gmpartsdirect.com/results.cfm?addtocart=1&addpartnumber=12499225&partnumber=12499225

[tayto]

OK, reread everything. The long travel lifters you are referring to are for a small base circle camshaft. This keeps them from dropping out of the lifter bore. Comp doesn't offer a cam shaft with a base circle small enough to allow that to happen in the OE hydraulic roller line up. Comp makes 2 lifter sets, a OE style p/n 850-16 same as what you have, and a 'short travel" p/n 875-016. Those are what I went with as recommended by Comps Tech line...
OK I see my confusion now, I always thought the cam had a small case circle. Perhaps having OE lifters is the problem behind my oiling issue...


If they are still press-in stock studs they are 3/8" on a factory L31 Vortec head.
The machine shop removed the press-in studs and put in screw-in. They are only "jobber" studs, not ARP or anything fancy unfortunately.

So if I was to tear the intake off to replace lifters, do you think it'd be worth it to run thinner head gaskets to get my quench in order? Just seems 10.5:1 is high for iron heads and 91 octane. I also know you recommend running the vic jr 2bbl intake, any advantage to going to that over my performer rpm? Was told to go with the performer rpm and plumb coolant under the plenum as per rbob, which is what I have done. Also have a 195* stat.

[tayto]

bump.

[Fast355]

The machine shop removed the press-in studs and put in screw-in. They are only "jobber" studs, not ARP or anything fancy unfortunately.

So if I was to tear the intake off to replace lifters, do you think it'd be worth it to run thinner head gaskets to get my quench in order? Just seems 10.5:1 is high for iron heads and 91 octane. I also know you recommend running the vic jr 2bbl intake, any advantage to going to that over my performer rpm? Was told to go with the performer rpm and plumb coolant under the plenum as per rbob, which is what I have done. Also have a 195* stat.

10.5:1 is fairly high and requires a cooler than stock thermostat and careful spark advance tuning. I am not sure that I would really recomeend a smaller cam as the one you have should pick that car up and move it effortlessly and smaller will only kill your performance. In my experience a 10.5:1 engine with the proper .038-.041" quench had less detonation than a 10:1 engine with a .060"+ quench. But I also had a ton of cam in that engine and I am sure the dynamic compression ratio was under 8:1 which is pump gas friendly.

I like the Victor Jr but it definately requires a skilled tuner to get it to run well in all weather conditions. The performer RPM is a great intake, especially with heat plumbed into it.

I have had good luck with the Elgin E1136 in a heavy vehicle with a 9.5:1 350 Vortec and all stock running gear. However it is on a tight 110* LSA and has 4* advance built into it both of which make the intake valve close earlier and trap more cylinder pressure. In an engine over 10:1 I feel it is a poor match due to the dynamic compression ratio getting too high.

http://www.competitionproducts.com/Elgin-Chev-SB-Hydraulic-Roller-Camshafts/products/389/

If you want to try a different cam, consider a LT4 Hotcam, although I am not sure it would be worth the time to swap.

[tayto]

Will the LS7 lifters be sufficient for my cam or should i go with the short travel compcams ones? i seemed to have read mixed reviews when i googled them. I think I will leave the quench for now... would there be any point in going to the 7427 vs ebl? abd running tge MAF code?

[Fast355]

Will the LS7 lifters be sufficient for my cam or should i go with the short travel compcams ones? i seemed to have read mixed reviews when i googled them. I think I will leave the quench for now... would there be any point in going to the 7427 vs ebl? abd running tge MAF code?

Never have used the short travel comp cams units, however I have run the LS7 lifters and do run them myself. I have run them to .550" lift with 1.6:1 rockers and springs rated at 420 lbs open pressure at .580" lift using a seat pressure of 150 lbs. That would be a spring with 150 lbs seat pressure and 465 lbs/in spring rate. Using some math I am running 406 lbs open spring pressure. I have reved the engine to 6,500 rpm without issue. I am sure I am pushing the limits of the rollers on the lifters. I have heard anything above 350 lbs open is pushing the limits.

I would stick with the EBL if you have it. Your setup is mild enough that you should have no issues getting it dialed in with speed density.

[tayto]

So I should be fine to run the Ls7 lifters with my beehive springs then? Ive read reports that you need to get shorter push rods with the ls7 lifters. have you found this to be true? i will most likely check regardless. i would like to make sure my oiling issue is solved before i get a set of roller rockers.

[tayto]

Just the roller tip is a waste of good money IMO. I would go with the comp ultra pro magnum self aligning. The fulcrum is where most of the friction losses occur and the stamped steel rockers deflect under high lift/high spring loading. You said you didn't want a $500 rocker setup, the ProMagnums are $339.00 shipped through Jegs. My old recomendation would have been the Crane Gold narrow body LT4 style rockers, but since Crane relaunched they believe their stuff is made of silver, gold and platinum and pricing reflects it. I like the Pro Magnums because they are steel and will not fatigue as easily as an aluminum rocker.

http://www.jegs.com/i/COMP+Cams/249/1618-16/10002/-1
Hey fast getting ready to buy new lifters and change them. Wanting to get roller rockers the stamped ones were pirchased because i could not afford good ones at the time. Will the pro magnum roller rockers clear the stock valve covers? Did you have to enlarge push rod holes on vortec heads? If so I'll have to do them in car when i have intake off. I will also check push rod length at this time.