500hp pump gas NA SBB is it possible.

With nitrous, 500hp would be easy.

 

Before this site got hacked there was someone who did MUCH experimenting with the SBB. I believe his name was Bill & by the time he was done he ended up with 1200HP to the surprise of himself & MANY others. At this HP level he was starting to see the effects of this HP, but stated that with a front & midplate he believed there would no further be a problem.

Tom T.

 

Made about 450 to the tire with a 150 shot. Went to the track and went 10.98 @ 120 .

 

My car has been turbocharged for about 15 years... the only damage to the engine has been 3 head gasket failures when I cranked the boost up and revved it higher to see what would break. This was with a stock bottom end and home ported heads with stock valves, small can, 7.8:1 compression, completely streetable. Pump gas, idles like stock, puts 450 Hp to the tires on low boost.

I had a professionally built short block built for the upcoming alum heads. I used a 1 inch thick block girdle, billet crank by king, Herche forged rods, diamond pistons, external belt driven oil pump, alum oil pan etc.. it will be fully streetabke, 9.3:1 compression, custom cam, very mild till boost hits. I am getting the first set of alum heads released to the public and they will be fully ported by Chris Skaling who is a porting pro. I went all out just because I wanted the build the best 350 ever, many people may not have the disposable cash for a toy like this, I get it. I expect some good numbers, should push my 2980 pound Skylark well.

All that said I don’t think all the $ I spent are necessary for a more mild build... in fact my old car that I sold had a $2000 turbo kit on it, 355 cube Buick 350, trw forged pistons, stock 74 rods with ARP, external balance, stock heads, poston 114 cam, single plane intake, did 460 hp at the tires, with a 2004r trans and 3.42 gear it ran low 11s with traction issues down half the track. It was about a $2500 engine, it lived a happy life till the new owner wanted more and went to a 383 striker with twin turbos, now 1200 Hp.

 

Yes Tom just to clearify it was 1021 hp on the engine dyno. They did find some front to back main cap movement during tear down inspections. This shows that a girdle is advisable in high Hp applications. Then they put the engine in a car and cranked up the boost and ran 8 second quarter miles...

There is a guy in puerto rica who has a single turbo Buick 350 and he runs reliably at about 640 hp.

Bobb mackleys son has been at about 600 Hp with a procharged 369 cube Buick 350 and no girdle.

 

Since a lot of you 350 guys are wondering what the new heads will do for you, and no on has mentioned it.. there is a simple proven formula for head flow vs HP for Non-boosted engines.

Pump gas, high torque cammed (smaller than optimum for high rpm power) engines-- take the Peak CFM and mulitiply it by 1.5-1.6. This pans out on several actual Buick 350 builds I have done. And dozens of big blocks.

For no compromise, high compression race stuff, with goodies like thin rings and vaccum pumps your going to be in the Max cfm x 2.2-2.3 range. Generally regardless of engine type.

There are only 2 known and accepted exceptions to these rules. Super High rpm small displacement stuff (NHRA comp eliminator motors) and the NHRA Pro Stock 500 cube engines.

These highly refined combinations produce typically 2.5 to 2.6 HP per cfm.

If anyone ever claims higher than a 2.6HP per cfm of head flow at peak, with no boost, then you need to throw a hairy eyeball on those claims. Could be a unicorn, but not likely.

JW

 

Nice info Jim!

So with an optimized sbb say 368 cid sbb 350 stroker with 225 CFM of intake flow and a hyd. roller cam in the low 240s intake and low 250s ex. degrees duration @ .050"/ with a vacuum pump running with solid roller lifters and roller rockers with the lift in the .680s, forged pistons with the thin rings, after market light weight forged rods, internally balanced with enough compression that it needs 93 pump gas that is the highest pump gas available here spinning to 7,500, you think the HP could be a factor of 2x for the CFM or possibly a bit more?

With the above and a set of well ported factory cast iron heads that flow in the 260 intake CFM range, 500 + pump gas HP shouldn't be a problem IMO. If your porter can get more than 260, it just gets easier to make that 500 on pump gas, just realize that the less cubes you have, the more you'll need to spin it to make that kind of HP naturally aspirated and cast iron rods don't like to spin much more than 6,000.

Anyone looking at nascar take out rods, make sure they have a .748" or bigger wristpin bore(.787" pin bore would be better as a minimum but if the rods are under $100 that have the .748" pins, that might be to good of a deal to pass up?) and that the big end is at least .900" wide so they can be machined to the proper offset when narrowing them. If they are zero offset rods to start with that are .900" wide, all the material to take them down to .845" needs to be removed off of the non-chamfered side. Also with a sbb 350 stroker look for rods that are in the 6.300" to 6.400" range so clearancing for the cam is minimal. 6.450" rods have been used for a stroker build and they needed clearancing like the sbb 350 Molnar rods do.

A sbb 300 stroker with a stroked sbb 350 crank, the 6.200" nascar take out rods are a good choice that will have plenty of cam clearance. The shorter the rod, the more it will actuate away from the cam as the crank rotates. Of coarse a longer rod can be used with a sbb 300 stroker but the rods may need a bit of the same clearancing as a sbb 350 would need using a sbb stroked 350 crank.