hey i just bought an engine out of a 96 caprice and i just found out they made a 4.3 that looks just like the 5.7 how can i find out if i have the 5.7 or the 4.3 i dont have the vin number to the car the numbers on the block say 43006 f61 j2435

 

there'll be "327" cast into the block on the side if its an LT1. If its not there or different you have the L99 or "baby" LT1.

 

is that 4300 number behind the drivers side head? If so it is an L99 the 4.3L motor the LT1 says 5700 there. The 327 on the srivers side of the block is a good check too the L99 says 588 in the same area. On the front of the block though they both have 327.

They share a good number of parts the block and heads crank rods are not among them though but are of the same construction. The L99 rods are 5.94 almost 6" but not quite a lot of guys have been sold them as 6" at swap meets and such.

If you want to know more ask away, my car came with one and I gave it a pretty good disection after dropping an LT1 in it's place.

 

thanks guys i have an idea i was thinking of using the crank in a lt1 destroking it to a 302 4 inch bore with 300 stroke it might run pretty good off the line would be radical oh by the way it is a 4.3 only paid 400 for the whole thing accessories and all pcm radiator all of it

 

Just part the motor out and take the money and put it towards a 350, you'd be much better off.

 

One of the b-body guys built a motor like that was not really aiming for a screamer but still the results are sort of disappointing. To make such an engine work you will have to spin past our engine managements capability.