Low numbers for an 427?
Static compression might be higher than that, maybe in the 11.3 to 11.6 range depending on piston height to deck and final cc of head chamber.
Based on your build sheet,
4.125" Bore
4.0" Stroke
6.125" Rod
-2cc piston
GM MSL gasket (0.051" thickness ; 4.150" bore)
240 / 256 113+4 camshaft
Based on your build sheet,
4.125" Bore
4.0" Stroke
6.125" Rod
-2cc piston
GM MSL gasket (0.051" thickness ; 4.150" bore)
240 / 256 113+4 camshaft
They can also be manipulated to read higher or lower than what's actually being made which is another reason for looking at some timeslips which even those aren't 100% bulletproof but at least it can let you know if there's any shenanigan's going on.
How's your air and fuel situation?
I did something similar to you with a second LS swap into an old car. Reused the air intake and fuel system from old engine, and the new engine felt really similar to old, stuck around 500 RWHP. Had to upsize intake feed tube from 4" to 5" to bring MAP losses down. And the spark plugs showed engine was running lean even though AFR was hitting target. Saw fuel pressure was dropping above 5000 rpm, so uprated the fuel pump. Engine sucked down a lot more fuel (I mean a lot) and I was able to add timing and the engine took off in the upper rpm's.
I did something similar to you with a second LS swap into an old car. Reused the air intake and fuel system from old engine, and the new engine felt really similar to old, stuck around 500 RWHP. Had to upsize intake feed tube from 4" to 5" to bring MAP losses down. And the spark plugs showed engine was running lean even though AFR was hitting target. Saw fuel pressure was dropping above 5000 rpm, so uprated the fuel pump. Engine sucked down a lot more fuel (I mean a lot) and I was able to add timing and the engine took off in the upper rpm's.
Last edited by QwkTrip; Jun 27, 2021 at 11:19 PM.
