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I'm working on a 5.7 K L05 engine thats a 638 block. Already set up for a roller cam but running a stock flat tappet. I already have everything to switch it over to roller but I have a stock Vortec (Bbody) cam I'd like to use. Obviously tuning is needed, even with the stock cam but has anyone run this cam with tbi on a stock tune? Its pretty damn small cam
'88 K1500 5.7L
Vortec short block, including cam, but with TBI damper and timing cover
ZZ4 intake manifold, Trick Flow Twisted Wedge heads w/ 1.6 rocker arms. Edelbrock "TES" Shorty headers, 3" high-flow catalyst and exhaust pipes/muffler. Heated O2 sensor. 4 degrees initial timing instead of zero.
Stock tune plus a few extra PSI of fuel pressure. The colder it gets, the more I think I may need to jack-up the fuel pressure some more. Ran great last summer/fall. Probably "needs" a custom computer chip, and maybe another couple of degrees of advance. Not going to get either until spring; unless the really-cold weather to come, makes it run worse than the mild bog I have now as the engine warms-up. Runs fine when fully-warm, runs fine totally cold. But as it warms up, there's a bog on acceleration and after each shift.
Well I'm not planning on going that extensive with the mods with this. I think with the performer egr intake I have, the L31 cam and some shorty headers is probably as far as I'm going to go as this is just my tow rig. Eventually I will get an EBL FLASH and tune it properly, I just need it to run ok till then.
It should be fine. That is the same cam as 91-93 B-bodies and Tbi, so the vacuum signal should dictate a easy swap. Probably not much gain though.
91-93 B/D-body used the 305 TBI peanut roller cam unless it was a 9C1 which used the L98 cam. The "Vortec" grind first came out in the 94 B/D body iron headed L99 and LT1. I have Vortec in quotation because the iron headed gen 2 grind cam is not exactly the same as the Vortec truck cam but extremely close.
I think I should clarify that this engine isn't going into a thirdgen. It's going in a 92 K1500 that came stock with the L05 with the stock flat tappet cam and 350 ecm
I think with the performer egr intake I have, the L31 cam and some shorty headers is probably as far as I'm going to go as this is just my tow rig. Eventually I will get an EBL FLASH and tune it properly, I just need it to run ok till then.
Originally Posted by robertfrank
It's going in a 92 K1500 that came stock with the L05 with the stock flat tappet cam and 350 ecm
Does that intake manifold have the correct bolt angles to fit the TBI heads? If not, you're in for some die-grinder work. Or just use the OEM manifold which will likely save you money on EGR and TBI adapters, too.
Depending on what manifold you have, you'll probably have to move the EGR valve rearward to clear the IAC motor on the throttle body. https://www.summitracing.com/parts/edl-1476
And you'd need a TBI-to-Carb adapter plate. Again depending on the intake, this could be a square-bore carb adapter or a Q-Jet carb adapter. Both styles have choices for where the throttle body is positioned. The throttle body can be centered, or offset.
Example: https://www.summitracing.com/parts/trd-2211
Does that intake manifold have the correct bolt angles to fit the TBI heads? If not, you're in for some die-grinder work. Or just use the OEM manifold which will likely save you money on EGR and TBI adapters, too.
Depending on what manifold you have, you'll probably have to move the EGR valve rearward to clear the IAC motor on the throttle body. https://www.summitracing.com/parts/edl-1476
And you'd need a TBI-to-Carb adapter plate. Again depending on the intake, this could be a square-bore carb adapter or a Q-Jet carb adapter. Both styles have choices for where the throttle body is positioned. The throttle body can be centered, or offset.
Example: https://www.summitracing.com/parts/trd-2211
Luckily I already have everything mentioned lol. I also already modified the middle bolt holes
Does that intake manifold have the correct bolt angles to fit the TBI heads? If not, you're in for some die-grinder work. Or just use the OEM manifold which will likely save you money on EGR and TBI adapters, too.
Depending on what manifold you have, you'll probably have to move the EGR valve rearward to clear the IAC motor on the throttle body. https://www.summitracing.com/parts/edl-1476
And you'd need a TBI-to-Carb adapter plate. Again depending on the intake, this could be a square-bore carb adapter or a Q-Jet carb adapter. Both styles have choices for where the throttle body is positioned. The throttle body can be centered, or offset.
Example: https://www.summitracing.com/parts/trd-2211
Luckily I already have everything mentioned lol. I also already modified the middle bolt holes
Whats funny is I already have that too lol. I got it for free out of a boat built 305 that had almost zero hours on it. Im saving it for a swirl port headed, TPI ramjet cam build.
Thought I'd give an update. Got everything together and it runs really well with 13psi and the timing about 4 degrees advanced. It does have a touch of a stumble when its cold but after it warms up its fine. I can tell it could use a tighter tune but as if now it's fine. My ultimate plan is to swap in an LT1 355 that I already have waiting in the wings, it's just not fully done. I'll be either running the carb LT1 intake with an adapter plate and a 454 TBI unit OR I may redrill the heads for an sbc pattern and run a TPI intake I have. Still debating.
11-25-2021, 07:32 PM
