Head Swap Options For 5.7L 350 TBI Engine

[Majoraslayer]

I am not familiar with the LT1 cam specs, maybe @L31MaxExpress could chime in, I believe he is familiar with both cams.

I will be using the 8801 in a 383 with Summit/Dart heads, Edelbrock intake, 46mm tbi and the ebl flash in my son’s truck. Should be getting to the engine in about a month.

For reference, according to what I've seen on the CamaroZ28 forums the stock LT1 cam specs for a '93 model should be 202/207 @ .050" .450/.460 lift 116 LSA. I've seen a couple places mention the max lift on that is .480, but I can't find where I saw it at the moment.

 

[tayto]

.450s sounds right, i think stock LT1 heads were good to .480 lift without modifying IIRC

 

[L31MaxExpress]

For reference, according to what I've seen on the CamaroZ28 forums the stock LT1 cam specs for a '93 model should be 202/207 @ .050" .450/.460 lift 116 LSA. I've seen a couple places mention the max lift on that is .480, but I can't find where I saw it at the moment.

There are like 3 grinds for the F/Y-car LT1 and 1 for the LT4 engine. You are hitting it on the nose. Melling has a real nice cam spec list for the OE replacement clones with full details at both 0.006 and 0.050 duration.

 

[Erik the Awful]

I know that I have said this before but, I would keep it simple. I would have the tbi heads rebuilt with some good valves and beehive springs that match whatever roller cam you end up using... Possibly have the heads machined for screw in studs and get some roller rockers.

One of the benefits of beehives is that they're only about 10% stiffer than our stock springs. You don't need screw-in studs unless you plan on spinning it hard or just don't trust the press-ins.

 

[L31MaxExpress]

One of the benefits of beehives is that they're only about 10% stiffer than our stock springs. You don't need screw-in studs unless you plan on spinning it hard or just don't trust the press-ins.

Definitely agree. I have run Pac1218s on Comp 787 retainers, 0.050" offset locks, 0.550 lift and turned 6,500 rpm without ever worrying about pulling the OE studs.

 

[Majoraslayer]

Funny little update, I just went through all of the pull-off rocker ams to check them out. There was one random self-aligning rocker arm mixed in with all of the other flat-bottom rocker arms.

Also, the LT1 cam turned out to be too damaged to reuse. I guess that means I'm in the market for something comparable, because a stock spec '93 LT1 camshaft is at least $360.

Also also, because I'm an idiot, I'm set up to meet another guy for some 906 Vortec heads this weekend. My instincts tell me, based on how cursed everything else has been so far, at best one head will be bad and one will be good. Then I'll be stuck with an 062 head and a 906 head, and no one anywhere near me with a good match for either one lol

 

[98 Nitro]

906 and 062 are the same head anyway so no problem there, I think the difference in casting #s is two different plants.

 

[L31MaxExpress]

Funny little update, I just went through all of pull-off rocker ams to check them out. There was one random self-aligning rocker arm mixed in with all of the other flat-bottom rocker arms.

Also, the LT1 cam turned out to be too damaged to reuse. I guess that means I'm in the market for something comparable, because a stock spec roller replacement camshaft is at least $360.

Also also, because I am idiot, I'm set up to meet another guy for some 906 Vortec heads this weekend. My instincts tell me, based on how cursed everything else has been so far, one head will be bad and one will be good, leaving me with a 062 head and a 906 head and no one anywhere near me with a match for either one.

906 and 062 are the same head anyway so no problem there, I think the difference in casting #s is two different plants.

Well thats never fun. There can be as much as 30+ CFM difference between Vortecs depending on where they were made. The Hecho en Mexico heads flow like garbage and are prone to cracking, the Canadian 906s flow the best.

 

[98 Nitro]

Ya sure but I believe he is talking stock heads not Mexican Vortecs so no real difference. I still think his best bet buy new heads either Jegs Vortecs which are less $ than the GM Mexican ones, or Trick Flow 87-95 heads and no worries about changing intakes/water pump but obviously cost more
Now if he knows someone that has a good set of original Vortecs or a good set of TPIs that were worked over then by all means go used but otherwise buy new.

 

[L31MaxExpress]

Ya sure but I believe he is talking stock heads not Mexican Vortecs so no real difference. I still think his best bet buy new heads either Jegs Vortecs which are less $ than the GM Mexican ones, or Trick Flow 87-95 heads and no worries about changing intakes/water pump but obviously cost more
Now if he knows someone that has a good set of original Vortecs or a good set of TPIs that were worked over then by all means go used but otherwise buy new.

Its is hard to say for certain what a pair of used heads came on. Could be from a truck, boat, industrial engine like a generator or compressor, loads of the Vortecs get pulled off much newer marine engines that were not winterized. I have bought 3 pairs over the years off marine engines that cracked blocks, usually as the whole engine dirt cheap. The crank in the L31 I just built is out of a L30 305 marine engine that had ~75 hours on it and met it demise during the owners nasty divorice. I was able to use the 305 crank because I used the lightweight LT1 flat tops.

Last year I bought a freeze cracked 6.3L Mercruiser, same as a HT383E with 60 hours on it, complete with the marine intake manifold for $500 for the same reason.