Thread: recomended rebuild, i have 225 heads

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Originally Posted by flanker1970

I have a 406, 10.6 to 1 compression, hyd roller 236/242, dart 215 cc platinum heads, zero decked, flat tops. It's in a 3900lb car with 2500 converter and 3:42 rear. The car pulls very hard but needs more gear and I can't help but think of torque that i am probably missing out on with those 215 runners. A friend swore that those were the one's I needed as a more aggressive solid roller may be in the future. Currently, i like the cam and am kinda making the best of the heads. Wish they were a bit smaller though...say 200cc

Different ball of wax. You have a larger bore, which will flow more cfm than a smaller bore like a 350 block. Plus, you have another 50 cubic inches. Looks to me like a very close to optimum combo, with the exception of like you said, needs more gear. I have to believe that you engineered the motor with a very tight squish to operate on pump gas, because running your stats through the KB Dynamic Compression Ratio calculator yields an 8.864:1 DCR.
RPM HP TQ
2000 151 396
2500 191 400
3000 242 423
3500 308 462
4000 372 488
4500 426 500
5000 465 488
5500 490 468
6000 491 429
6500 458 370
Peak volumetric efficiency 98.9% @5000
Peak BMEP 184.5 @4500
If you can make 400 ft/lbs at 2000, you have an excellent street combination. You're only off 4 ft/lbs from that. Good job! I used a 750 carb, RPM intake and 1 3/4" headers to run this Sim.

Those hydro rollers don't like much over 5,500 with the stock spider retainers.