70 318 with 340 internals/Cyl Head

I have a teener with 340 heads, not enough compression. 4.56 gears with a spool. Hits 100 mph at the 1/8 mile mark and will not accelerate any more plenty of rpm left in 3rd gear of a 727 with a manual valve body. Motor was built with swap meet parts. Should have decked the block and milled the heads, but didn’t. Its alot of fun up to 100 mph though.