Head Swap Options For 5.7L 350 TBI Engine

[Majoraslayer]

The take-off heads were TBI heads. I'm going to be installing Vortec direct replacement aftermarket heads, and changing to a roller cam setup on an LT1 cam. It shouldn't be much different from a factory Vortec when done. From what I've read, Vortec heads are basically the same as LT1 heads except set up for regular coolant flow, and the cam should only be a very mild upgrade over Vortec. The rocker arms I pulled off the LT1 heads were definitely self-aligning. The fact that the rocker arms I pulled off the TBI heads had such a wonky wear pattern on them indicates it probably SHOULD have had the self-aligning rocker arms as well like you said, but for whatever reason it didn't. The ones I ordered to replace them for the Vortec heads I'll be using are definitely the self-aligning rocker arms.

 

[Majoraslayer]

Actually, now that I think about it, there's a good chance the previous engine owner probably did something in there, which could include putting the wrong replacement rocker arms in. I noticed recently I had two oil caps, so at some point the driver side valve cover was lost and they threw on a spare passenger cover. That confirms they had the covers off for some reason, and also that they probably had no business taking the covers off lol

The lifters looked perfect, so they may have installed all new lifters plus the wrong rocker arms. I bet someone was chasing a lifter tick.

 

[L31MaxExpress]

The take-off heads were TBI heads. I'm going to be installing Vortec direct replacement aftermarket heads, and changing to a roller cam setup on an LT1 cam. It shouldn't be much different from a factory Vortec when done. From what I've read, Vortec heads are basically the same as LT1 heads except set up for regular coolant flow, and the cam should only be a very mild upgrade over Vortec. The rocker arms I pulled off the LT1 heads were definitely self-aligning. The fact that the rocker arms I pulled off the TBI heads had such a wonky wear pattern on them indicates it probably SHOULD have had the self-aligning rocker arms as well like you said, but for whatever reason it didn't. The ones I ordered to replace them for the Vortec heads I'll be using are definitely the self-aligning rocker arms.

Not all that different from the "Budget L31 Build" I just got fired up a running. I used a GM 6492' roller cam that is similar to a LT1 cam in specs, the LT1 flat top pistons, and 1.6 roller rockers. Made for an engine that runs very tamely. It is pulling 19 in/hg vacuum at 650 rpm and is a very smooth, responsive runner.

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[Schurkey]

The heads that had the non-self-aligning rockers, probably also have the tips of the valves worn goofy.

Sometimes that results in catastrophic failure, when the rocker goes completely off the valve tip, maybe knocks the valve retainer loose, and the pushrod falls out of position and bends.

 

[Majoraslayer]

Not all that different from the "Budget L31 Build" I just got fired up a running. I used a GM 6492' roller cam that is similar to a LT1 cam in specs, the LT1 flat top pistons, and 1.6 roller rockers. Made for an engine that runs very tamely. It is pulling 19 in/hg vacuum at 650 rpm and is a very smooth, responsive runner.

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Where did you get that cam? The lobes on my LT1 cam all look to be in spec by the naked eye, but I'm going to have it checked out at the machine shop due to some scoring on the bearing surfaces. I may look at that cam as a backup option if my LT1 cam is too bad.

 

[L31MaxExpress]

Where did you get that cam? The lobes on my LT1 cam all look to be in spec by the naked eye, but I'm going to have it checked out at the machine shop due to some scoring on the bearing surfaces. I may look at that cam as a backup option if my LT1 cam is too bad.

From GM. It was a $100 cam a couple of years ago. I just searched it by part number, currently showing unavailable. Hope that does not mean it has been discontinued because a lot of people have been scooping them up over the past few years for budget builds like this since we have known they existed by that part number.

F (S)Camshaft 94666492 | TascaParts.com

94666492 - F (S)Camshaft

www.tascaparts.com

 

[Majoraslayer]

From GM. It was a $100 cam a couple of years ago. I just searched it by part number, currently showing unavailable. Hope that does not mean it has been discontinued because a lot of people have been scooping them up over the past few years for budget builds like this since we have known they existed by that part number.

F (S)Camshaft 94666492 | TascaParts.com

94666492 - F (S)Camshaft

www.tascaparts.com

I'm having a similar problem with backup LT1 cams. I can't seem to find them used anywhere, and brand new replacements are running around $530. Posts from just a few years ago seem to reference they were dirt cheap everywhere not that long ago.

 

[SNCTMPL]

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, whether it’s the LT1 or maybe a Summit 8800 or 8801. Possibly have the heads machined for screw in studs and get some roller rockers. Then get an Edelbrock tbi intake, that is the key to keeping it simple. All the brackets bolt up, the egr works, everything will be plug n play. Your ultimate tbi mods and ebl flash, and that will be a good running full roller 350.

Edit: That is the voice of reason in my head after building a few that were not that simple, and wishing they had been.

 

[Majoraslayer]

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, whether it’s the LT1 or maybe a Summit 8800 or 8801. Possibly have the heads machined for screw in studs and get some roller rockers. Then get an Edelbrock tbi intake, that is the key to keeping it simple. All the brackets bolt up, the egr works, everything will be plug n play. Your ultimate tbi mods and ebl flash, and that will be a good running full roller 350.

Edit: That is the voice of reason in my head after building a few that were not that simple, and wishing they had been.

I may have mentioned before, but I still have a very loose grasp of reading cam numbers to compare them. It looks like the Summit 8800 has a similar lift to the LT1 cam (I see .480 thrown around on both), how would they compare performance-wise? I do like that $279 price tag a lot better than the other alternatives I've seen if I find out my LT1 cam isn't usable.

 

[SNCTMPL]

I may have mentioned before, but I still have a very loose grasp of reading cam numbers to compare them. It looks like the Summit 8800 has a similar lift to the LT1 cam (I see .480 thrown around on both), how would they compare performance-wise? I do like that $279 price tag a lot better than the other alternatives I've seen if I find out my LT1 cam isn't usable.

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.