i bought a 383 from a local guy last week for my sons street 1973 c10. he ran it on the street for a couple hundred miles and decided that $8 a gallon fuel wasn't going to work. He built the motor with around 11.5 to 1 compression. my calculations come in at 11.4. my question is can i run this on the street on premium with these heads and if the tune is right. or should i lower the compression. If the answer is drop the compression, whats the most cost effective way to loose a point of compression. open up the heads combustion chambers. install dished piston(which I'm going to have to re-balance the assembly (looks like the pistons are about 20g difference.) thicker head gasket and ruin the quench. switch to e85. or any other suggestions.this is what i know is in the engine.scat 9000 crank 3.75 stroke5.7 h beam rodsprobe fps .060 over forged pistons 1.425 compression height -4cc flat topshe says the block was at 0 deck heightpatriot 64cc 210 intake headsLunati cam (summit # lun 10120704lk) 110 lobe sep. 504 intake lift 525 exhaust lift. duration at 050 233int 241 ex1.52 aluminum rockersarp boltsperformer rpm intake850 Holley QFT vac sechow do i make a good reliable street motor out of this combo. I also have a another block that I'm guessing is 30 over.
You can do it with another camshaft a couple of ways. You can replace your present camshaft with one of the same specs but with a wide lobe center like 113-114, or go to a bigger at .050 camshaft. Either way it will bring down the cranking compression and lower speed cylinder pressures, allowing you to run pump gas. Have you done a compression test on your motor? If its about 190lbs or less it may run on pump gas. Have you tried running it on pump gas?