lol the ls7 story
heres the rundown. My dad found a complete never fired ls7 crate engine sitting in some guys basement that he had bought but never installed in anything. This motor still had the crayon markins on the domes of the pistons when it was installed, only thing missing was the original cam. So he bought it. Now this was @ about 2 years into the resto. About a year later my dad canceled an order on a 2002 z06 @ Kerbeck ( i found the same car for sale local). they would wouldnt refund his deposit so he used the money to order GM performance products aluminum rectangle port heads with 2.25/1.90 valves to replace the stock iron heads on the ls7. I found a cam on ebay and we were all set. LS7 shortblock+GMPP heads+L88 intake+1967 L88 carb.
Fast forward a few years. We fire the car up and right from the get go the motor never ran right. Backfired through the intake, wouldnt idle, etc.... In fact there is still burn marks on the underside of the car from a few of the bigger backfires, i know dad i still have to clean those up
. So we replace the ingnition setup with a pertronix setup and it runs alot better but still never good enough. After weeks of scratching our heads we finally figured out the problem. The springs installed on the new head we got were for a hydrolic lifter setup and the ls7 had a solid mechanical. Now i had checked the lift ratings and we were in the clear but what i didnt check was what the seat pressure ratings were. Turns out they were way off and the extra pressure flattened 3 of the lobes on our cam shaft. So we ordered up a new comp cam (255/
[email protected] .620"/.620" 110lsa) and converted the rest of the valve train to a full roller rocker setup. Car ran alot better and we thought we were in the clear.........till a few weeks later my dad was showing off to his friends and the motor seized up and he had to push it home with his buddies. Guess the metal from the flattened lobes finally made its way to the main bearings. So in the end the motor caused alot fo headaches and has lived a very rough life in those 62 miles it was alive and kicking it in the SS.
The motor is currently @ the machinists getting reassembled with some more displacement (468) and some more compression (13:1) but i dont think it will ever end up in the SS again. this ls6 is a much much more docile setup with much better street manners. Had planned on putting it in my 94 Z28 but after adding up the costs its just not worth it.