What do you all think about using a LT1 engine (SB Gen2) and drilling a hole in the stock LT1 intake for the TPI distributor and using the TPI computer, distributor, and sensors on an LT1 block? The reason I was thinking about doing this is my L98 engine is beginning to die, and you can get lt1's for pretty cheap. Also I could put a 383-stroker kit and an LT4 hot cam and it would be pretty sweet.

The main reason I was thinking about a LT1 instead of a L98 is because I don’t like how the TPI intake power dies off so fast and some people are having problems with LT1 intakes on the L98’s, like coolant leaks and exhaust leaks through the EGR port on the heads. Also LT1’s have pretty high HP stock.

Questions:
-Which LT1’s have 4 bolt mains and aluminum heads?
- Do all LT1’s have the bad “pink rods”?
- Can I mount the serpentine belt setup to a LT1? I know that the LT1 water pump is cam driven so I would have to get a shorter belt, but would everything else work?
- Did GM make any revisions to the LT1 block, if so which year is the best to buy?

 

What problems do you have with LT1's management system?

 

Honestly, I'd use the LT1 computer if you're going to do the swap anyway. Because if you use the stock computer you will have to do a LOT of reprogramming to get it to really run, and you're still limited by the Thirdgen ECM. The LT1 computer is much more advanced, and has a lot more control when it comes to controlling the fuel and spark curves. Plus you get the added benefit of sequential fuel injection for a little better gas mileage. And the LT1 computer will already be programmed for the LT1 engine right off the bat.

Answers:
- All F & Y-body LT1's have aluminum heads, the B-bodies had iron I believe. Also, I think only the Y-bodies had 4 bolt mains (if any did)
- I think only the LT4's got the PM "Pink" rods (and why do you say they're bad? I had always heard they were good)
- I would think you could mount our serpentine setup to an LT1, but I don't know for sure.
- I think all of the LT1 blocks are the same

On a side note - if you do go with an LT1 computer get a '94 or '95. Those are the best two years (MAF & MAP setup, OBD I - meaning only two O2's instead of four)

 

1 - Only Y-body (Corvette) got Aluminum heads and 4bolt mains.
2 - 92 and 93 LT1's actually had VERY nice forged rods. All other years got powdered metal rods, which are still nice. None of them came with the 'pink' style rod.
3 - You could reuse the factory serpentine. You CANNOT use the factory TPI serpentine on the LT1. The cam driven water pump interferes with the belt routing.
4 - There are 2 known castings. they are for the LT1 (5.7) and the L99 (4.3). They look the same, but on the back, in the casting it will say 5.7 or 4.3.

I went to MorTec and checked the casting numbers and got this:

# cid year mains notes:
10125327...350...92-up...2 or 4...Gen.II LT1, reverse flow cooling
10125327...350...96-up...2 or 4...Gen.II LT4, reverse flow cooling
10168588...265...94-96...2......... Gen.II L99, Caprice, reverse flow cooling

So all the 1992 - 1997 LT1/4 blocks are the same casting. Just machined differently for 2 or 4 bolt mains.

There you go.