Originally Posted by wildeman
I have asked this question a while back, but now I have some more info on my motor. I currently have a 355 sbc with SR torquer heads (76cc, 2.02/1.6, 171cc intake runners) street port/polish, an Edelbrock Victor Jr, Holley 750 vacuum sec., Lunati cam with .480 lift int/exh 292 adv dur, 230@.050., and Sealed Power L2256F30 pistons. The motor came assembled with the Fel-pro blue gaskets (.040) and the motor is claimed to be a 10:1 400hp. With the heads, I'm thinking its about 370 and 8.5:1. I swapped out the gaskets for
.015 steel shim gaskets, but I figure I'm running around 9:1. I've been looking at the Patriot pn2168 aluminum head to get that 400hp or slightly more. Would these heads be a good choice or is there better for around the same price?
Crappy cam this looks like the Bracket Master this thing is all ramps and no action.
Heads are too big in the chamber you really need to pump up the compression. I don't know what the deck clearance is but assuming it's OEM at .025 inch even with your .015 shim head gasket you're at 8.8 static. With these pistons it would take 64 cc head to get to 10 which any decent cam is going to need.
You really need to change the cam to something like a Comp XE268 which gets on with lifting the valve quickly and holds it open late to pump up the ponies. You gotta get the compression up whether that's milling the crap out of the Torquer's or replacing them take you're pick. You need to know what the deck clearance is going because if this block is already zero decked that will control how much you mill on the heads. You've got to run the Dynamic Compression Ratio (DCR) for your compression ratio adjusted for the intake closing point. Later closing needs more Static Compression Ratio (SCR) to drive out a high enough dynamic. Aluminum heads need about one more point of compression than cast iron as they suck heat out of the combustion chamber way faster than does cast iron just in case you go that route.
Even with the Comp cam and decent 64 cc chamber heads it'll take 1.6 rockers perhaps with competent pocket porting, depends on whose heads many of these new heads are easier to screw up by grinding on them than you're likely to get more power from them, to get 400 horses from a 355 with the pistons you have, the Comp XE268, 1.6 rockers with the the Partiot 2168 heads , the intake set up you have, a pair of long tube 1-5/8ths tube headers should prove to be a no-brainer 400 horses on an engine dyno.