If I were to do a cam, what might be a mild - mild+cam I should look at? I have considering putting the Vortec heads on - The TBI cam is apparently notorious for being the sh!ttest cam that came in any small block -
How difficult is it to swap to rollers? Would valve springs be needed to get to an L31 ish spec?
The TBI cam isn't even .400 lift, and the heads aren't any better. If you want a mild bump in power you can port the heads, but at a certain point you're polishing a turd.
Always put new springs in a fresh build. If a rocker arm breaks or a pushrod bends you get a misfire. If a spring breaks you wreck the valve and piston.
Can you do a roller cam conversion with the motor still in the vehicle?
Anyone have reccomendations for a mild flat tappet cam, or would you only do a cam mod if I went roller? If so whats a good mild roller cam.
If you want to spend $500 on retrofit lifters, you can drop them in place of the flat-tappet lifters.
If you want to spend $40 on all the stock roller lifter stuff out of a junkyard motor, you'll have to drill and tap the oil gallery in the center of the lifter valley and install some allthread to fit the stock spider. If you're careful you can probably drill it without yanking the engine, but I wouldn't trust that metal shavings don't end up in the oil passage.
If anyone has experience putting vortec heads on a TBI what needs to be done to accomodate the swap?
A few years back I started a sticky on the differences. Be sure and read through it, because there are a lot of changes that I didn't get all in the first post.
"Can I swap a Vortec motor in place of my TBI motor and does it just bolt in place?" Yes, you can swap a Vortec motor in place of a TBI motor, but no, it doesn't bolt in place. So, what does it take? Head and Intake Differences: The Vortec manifold has eight bolts, two on each corner, drilled...
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I put Vortec heads on a late non-Vortec block that had 4-bolt mains and roller provisions. I used a Summit Racing carbed Vortec-style intake with a squarebore-to-spreadbore adapter with a TBI adapter plate on top of that. The TBI barrels are wider than a squarebore opening, but slightly smaller than a spreadbore opening. After failing to get the TBI to handle my larger cam I eventually went with a Holley Sniper.
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I absolutely recommend to drill the coolant bypass holes in the Vortec heads so that they're drop-on compatible with the TBI cooling system. If you don't do this you will need to run the Vortec water pump, which means re-routing the heater hoses. It's a pain in the butt. Really, only the passenger head needs the hole, but if you ever have the heads off again and get them crossed up you'll be fighting weird overheating spikes.
If going with vortec heads you will need a different intake due to the angle of the face on the head that mates to the intake being different.
Sorry, but the mating surface is the same. The bolt angles are different. The ports are taller, so even if you find a way to clamp the intake down the TBI intakes don't fit. The picture below is an intake mocked up on a block with a TBI head on the left and a Vortec on the right.
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There's more that I'm forgetting. Be aware that the Vortec timing chains are different, you'll need a cam button, and ?? There's a reason I started the sticky.
