New Engine Help

[Engine07]

Hey thanks for reminding me about eq heads. I am going to give them a call tomorrow and see if they can do something with a slightly larger chamber size. Mostly my issue with running a factory style vortec is the 64cc chamber size with cast iron. I need to lose some compression slightly, a 67cc should put me about 9.4:1, with the 64cc I would be around 9.62:1 which I was kind of wanting to lower a little bit with cast iron or either go to aluminum, I have actually been looking at the etecs too, I really like that head.

[lionelhutz]

Keith's comments on the LT1 hot cam are about what I think of it. I have a LT1 with that cam and I think it's a little lacking in the low end which is where you want more power for a truck. A cam that trades a little top end power to boost the low end power would be more suitable.

[Fast355]

That sounds like a sweet build fast. I had the thought of the s10 converter but my worry was if it would be strong enough or not to hold up behind the torque the engine would be pushing in the truck being as heavy as it is. Any thoughts on this as I have never tried it? Also back trying to line up cylinder heads again...the bow tie heads are no longer in production although everyone still has them listed I guess they were recently discontinued. I had promaxx email me their flow rates on some of their aluminum heads and they look pretty promising at 28" water. Never used promaxx before but looks like what reviews I can find from people that actually have them they aren't having any issues. Lot of mixed reviews but all of the bad ones I found those guys didn't own them just hearsay I guess. Their 180cc appears to outflow their 185 and close to their 190 but I believe if I read right it is mildly ported.

I have run one in a 99 C1500 Suburban and a 97 Express G1500 conversion van. Both over 5,000 lbs and both were undergeared IMO. I had more issues with the 4L60E but never a converter issue aside from the 38K mile factory converter in the Express that burned the lockup clutch out after the PWM valve started sticking.

[Fast355]

Keith's comments on the LT1 hot cam are about what I think of it. I have a LT1 with that cam and I think it's a little lacking in the low end which is where you want more power for a truck. A cam that trades a little top end power to boost the low end power would be more suitable.

The 383 vs 350 will make the same cam act 6-10* @ .050 smaller.

I have had the Hotcam in a few builds and never found it lacking on the low-end and it pulled hard in the mid-upper rpm range, right where your engine is going to be when you are accelerating uphill with a load or passing a vehicle on a two lane country road. Maybe my driving style is a bit different than most, but I would gladly make some extra power in the 2,500-5,000 rpm range even if it meant giving up some in the off-idle to 2,000 rpm range.

I have seen dyno testing on 350s from multiple builds using both the 218/228 Hotcam and the GM 846 equivalent 222/230 @ .050" cam and both are making 360 TQ at 2,000 rpm and 385 TQ by 2,600 with Vortec heads and a 9.4-10:1 compression ratio. The 383 will make a good 30-40 ft/lbs more torque over the 350 at that rpm.

[Engine07]

I'm about to order my cylinder heads finally, lol. After reviewing all of the options and parts used I am going with the edelbrock etecs. Nothing against the other heads looked at but these have some features I really liked and by the parts used they should be reliable and make good power. My compression should come in at around 9.7:1 which I think will be pretty good for aluminum headed daily driver. Was talking to one of my buddies what I was doing since I'm helping him out bolting an engine together and I wound up getting the hotcam. Gave him a hundred bucks for the cam new in box, a new water pump, and beehive valve springs with locks and retainers I'm sure will come in handy for the 67 c10. I'm definitely going to rebuild the trans once I get the engine running right before I lay into it. I don't figure it would take one good full throttle pull to destroy it. Do have some tuning questions though. Will a factory vortec timing table be a good place to start to get the engine running? I'm planning on big block throttle body with big block injectors about 25psi and a vortec fuel pump, uploading vortec timing table, and changing injector size to match what I have installed...sound like a good starting point? And when changing injector size in bin, do I put 80lb hr for the 454 injectors, or do I put the lb hr they are actually putting out at 25psi?

[Fast355]

I'm about to order my cylinder heads finally, lol. After reviewing all of the options and parts used I am going with the edelbrock etecs. Nothing against the other heads looked at but these have some features I really liked and by the parts used they should be reliable and make good power. My compression should come in at around 9.7:1 which I think will be pretty good for aluminum headed daily driver. Was talking to one of my buddies what I was doing since I'm helping him out bolting an engine together and I wound up getting the hotcam. Gave him a hundred bucks for the cam new in box, a new water pump, and beehive valve springs with locks and retainers I'm sure will come in handy for the 67 c10. I'm definitely going to rebuild the trans once I get the engine running right before I lay into it. I don't figure it would take one good full throttle pull to destroy it. Do have some tuning questions though. Will a factory vortec timing table be a good place to start to get the engine running? I'm planning on big block throttle body with big block injectors about 25psi and a vortec fuel pump, uploading vortec timing table, and changing injector size to match what I have installed...sound like a good starting point? And when changing injector size in bin, do I put 80lb hr for the 454 injectors, or do I put the lb hr they are actually putting out at 25psi?

I would start with the GM Performance Parts Ramjet 350 timing table. I have a copy of it somewhere if you want to go with it. It will run about well enough with the stock vortec timing table to tell you it doesn't like it at all.

[Roadknee]

I can post up the timing table from that 406 that I mentioned earlier. With the 170 etecs and 219/227 @ 0.050" 112 LSA hydraulic roller cam it should be pretty close. Set the Lb/hr to 90% of whatever the injectors flow at 25 psi. If you use their actual setting you'll end up with the high MAP areas of the VE table maxed at 100% and still won't have enough fuel.

What intake manifold are you planning to run?

[Engine07]

Would love to see those timing tables...that would be awesome!! I had no idea where to start with the tuning. Had read several posts where it looked like they were setting lb hr a little lower than actual flow but never saw a set amount or how much less, thanks. I am planning on using the performer rpm vortec manifold.

[Fast355]

I can post up the timing table from that 406 that I mentioned earlier. With the 170 etecs and 219/227 @ 0.050" 112 LSA hydraulic roller cam it should be pretty close. Set the Lb/hr to 90% of whatever the injectors flow at 25 psi. If you use their actual setting you'll end up with the high MAP areas of the VE table maxed at 100% and still won't have enough fuel.

What intake manifold are you planning to run?

I actually have Etec170s on the L31 shortblock in my Express with a 215/220 @ .050 cam in it. Not sure if my timing table will help though as the LS stuff does not use MAP for the load reference theu use GM/CYL air mass. The lowest point in my timing table is 12* with a very quick advance curve. I run within 4* of total advance by 2,600 rpm. I run 25* from 2,600-4,800 and climb to 29* by 5,600 and drop back to 26* @ 6,400. Cruise timing is pretty aggressive with 39* advance at the highest points.

[Roadknee]

I actually have Etec170s on the L31 shortblock in my Express with a 215/220 @ .050 cam in it. Not sure if my timing table will help though as the LS stuff does not use MAP for the load reference theu use GM/CYL air mass. The lowest point in my timing table is 12* with a very quick advance curve. I run within 4* of total advance by 2,600 rpm. I run 25* from 2,600-4,800 and climb to 29* by 5,600 and drop back to 26* @ 6,400. Cruise timing is pretty aggressive with 39* advance at the highest points.

That's similar to how we set up the 406 except it's running 31 total by about 3,500 rpm. A heavy truck might not get away with that much timing though. The 406 is in a 3,000 Lb. Nova and accelerates damn fast. It also likes 40° cruise timing by 2,000 rpm.

Fast - how did you determine the need to reduce timing past 5,600 rpm at WOT? Did it make better power or was that required to keep it off the knock sensor?

[Roadknee]

I am planning on using the performer rpm vortec manifold.

Heated plenum?

[Engine07]

I thought they all were except the air gap, but it doesn't look like any of the edelbrock vortecs are

[Engine07]

Professional products crosswind?

[brian617]

I thought they all were except the air gap, but it doesn't look like any of the edelbrock vortecs are

The Performer RPM Vortec can be setup to use hot water heated plenum.

Back when I was searching for timing tables to look at there was a alum headed LT1 map floating around on Third Gen, I saved it but cant seem to find it. I took a stock Vortec 5.7 and revamped it. It was decent in stock form, much better than a TBI map lol.

[Engine07]

By the hot water heated plenum are you referring to the water bypass being hooked from the water pump to the front of the manifold Brian?