Cam help for TBI 350

[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...umber=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/E.../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.