So we just bought a 86 TA .....The Original owner told me that he had someone put a 350 Vortec in it with the original TPI..... from what I read in the threads I'm wondering if that is something that can even work....The heads definitely seem to be Vortec as the valve covers have the bolts on top, and it looks like a standard GM TPI...... anyways the problem we are having is that the engine will stall while driving when I let off the gas.... it seems like its dropping to an idle but ends up stalling..... any ideas?? I adjust the idle stop screw but it only seems to work for a little while before it goes back to stalling..... other than the stalling problem it seems to run awesome.... Thanks
Sam

 

GM used centerbolt valve covers on every SBC from 87 on, so that is no indication that it's a vortec motor. The key is counting the intake manifold bolts. Vortecs use 8 instead of the normal 12. Your stalling problem sounds like a vacuum leak to me. Check all of your vacuum lines. If that doesn't work, spray carb cleaner around the common leak areas (hint: runner gaskets and baseplate gaskets) and listen for an idle change.

This can also be caused by other issues, but let's rule out the easy stuff first.

 

A standard GM TPI isn't going to fit a set of Vortec heads. Even if you modify the intake (or heads) to bolt up to each other, the runners will be off.

 

Only way of doing it

http://sdparts.com/details/scoggin-d...-center/sd3816

 

Okay I stand corrected

but in my defense, I am not very familiar with GM's TPI. What's the point of throwing vortec heads on with a restrictive intake (can't imagine the down low flow numbers from TPI to Vortec heads are much different).

 

The heads are substantially better than previous SBC heads. SD and a million magazine articles have shown that a bone stock L98 (stock heads, stock intake, etc) can pick up 40 horsepower by swapping to the Vortec heads and vortec TPI intake, due entirely to the better heads. The vortec intake flows about the same as the stock unported intake, but flows worse than aftermarket intakes. Because of this, the Vortec head swap doesn't always make a lot of sense if you consider the cost of the intake along with the heads, and the associated costs associated with bringing the heads up to a high performance level (spring swap, valve guide boss modifications, etc) when you could get aftermarket heads and an aftermarket base for not a lot more money. Where the vortec swap really starts to look attractive is in a case where you're doing a budget based engine swap and you have the opportunity to snag an L31 Vortec motor, or even if you're doing a budget head swap and can snag some used Vortec heads. Then this starts to really look appealing, especially if you can port the Vortec intake to help remove some of it's restrictions.