94 s15 build
 

have 86 454 fron 1 ton truck and 87 350 from 1/2 ton truck. either one any good to build

Both motors are good builder material. Is it your intention to do a swap into the S15?

S15
 

thats my plan. have 624 marine heads, heard no good. what about crank and rods from same marine 350

Unless you have considerable experience with engine swaps and setting up driveline and suspension systems, I would not recommend using a BBC in this little truck. A well-built SBC will move it along in fine style. Here are 109 dyno-tested SBC combinations built with static compression ratios that will be compatible with pump gas. Take a look through them and you'll begin to see what works with what.....
Ryan's Stroker Combo Page (108 and up!)
If I lived close to you, I'd bring my sledgehammer over to your place and smash those 624 heads so that nobody would ever make the mistake of using them again.

Here's a conversion manual that I highly recommend you reading before you ever pick up a wrench......
http://www.jagsthatrun.com/Pages/Che..._S-10_V-8.html

heads
 

found same heads (624) on my 80 3/4 truck. thats whats wrong with it. lost 1 cyl each side. thanks for info. prob put 454 in that