How much HP and torque would a person get with a:

Solid roller 346 (0.010 overbore and stock stroke)

Solid roller 392 (4.125” bore and stock stroke)

Solid roller 427 (4.125” bore and 4” stroke)


Figure the heads, intake, and exhaust can support any of the above (only compare bore and stroke and their resulting HP and torque). Figure the cam for the 346 is a solid roller version of a G5X3 and then go up from there for the 392 and 427.

 

I didn't think the GX3 was meant to be a solid roller cam...in which case you can go bigger. Figure in that you'll get about 10-15lbft more torque over a similar hydraulic setup with a solid roller setup (no hydraulic losses), but your hp would go up about 10% assuming a redline of 7400-7500rpm with the solid roller compared to a 6800rpm redline in the compared setup. Again, this is assuming that your cam is designed properly for the heads, and that they'll actually flow enough air to run at those rpms.

So...500rwhp should be possible with a 346. It only goes up from there.

 

A solid roller 427 makes my mouth water.

 

I'd talk with MTI and MORE for the big motor stuff.

MORE spun a 427 one to something like 8500 rpm to get all the benefit from the solid roller.

Which crank are you thinking about using?

 

With the LSX intake I'd think 600+rwhp is very possible with supporting mods.

With the new GMPP carb intake that will be out sometime next year...probablly a good bit more than the LSX at 8500 rpm.

 

You leave some unanswered questions. Pump gas? Race gas? Mix?

I'm speaking for the SR346, but you can expect anywhere from 450 to ~500 RWHP. Futral's motor put down 492 from a 346. Mine put down 458. Somewhere in there. You can definitely go bigger cam on a SR346. Mine's bigger, and idles great at 850. Little shudder below 1800 RPMs when driving, but that's what more gear is for.

Were I to do it over again, I'd probably try to swing a deal on some Patriot 59cc heads, and see if they'd set them up with 5/16" valve guides and have them prepped (by Thunder) for solid roller. That would leave the deck height pretty good, which works for P-V clearance. I'd go with some pistons that had bigger valve reliefs too. I'd still have Thunder put together and install the motor, though, they did a great job and have treated me VERY well. The GTP LS6 heads that I have are, frankly, about average performance for a rather high price. That's why I'd look in to the Patriots. But anyway. I'd try to keep the compression about 11:1 (pump gas, with a mix at the track).

The real question is... How fast do you want to afford to go? A bigger cube motor would have added significantly more $$ to my build up, and I had to draw the line somewhere...

-Andrew (expenses are already out of control as it is )

 

well it will be on pump gas (shitty 91 AZ gas ) but now and again will get some 100 in it (I have run an 11.2 CR for the past year without "too much" probublem).

8500 RPM!!!!!!!

I mentioned the G5X3 as a comparison (a solid roller version of a cam in that "size" idea)......though as a solid roller it would have faster ramp rates so....

what I was really looking for was a comparison of hp that is gained per jump in CI

ie: if a 346 makes 450rwhp, the 392 should make 550rwhp, etc.... (something like that)....