[Mike S]

Want to know if it is possible to make 700hp on pump gas with a factory block.
I am thinking of changing the heads for next year. Going from 330cfm to 380 cfm and of course a cam change. Need peak hp to be around 6500rpm. Right now I am running 12-1 comp with 72 cc heads. Looking at 80cc to drop comp 1 point.
The short block is factory, filled to the water pump holes, billet 4 bolt mains, forged 4.21 crank, lifter bore brace, crower rods and 60 over ross pistons.

Goal is to run what I am running now but on pump gas. 10.00/133 at 3400lbs in the heat of summer.

[RAIV-Z]

Yes, 4.35 Stroke, 4.150 bore, 470.72CID.
E-Heads by Jim Robertson.
10.5 to 1 Compression
Street Driven, pump gas.

Best so far, 10.409@128.68mph

[John Langer]

Possible, yes. Recommend, no.

[Jack Ferris]

4.25 x 4.25 stock 1970 block, 103 offset crank. 730 hp well over 1000 passes.

[firechickenman]

I'll say it could be done. I'm not quite to that level but getting close with a fairly basic street combo 455 (463). Studded 2 bolt block and factory "N" crank, 11-1, 325 E-heads, street roller cam with only .650" net lift. Regularly runs very low 10's @ 133 @ 3300 lbs. It would certainly be 9's with some East Coast air . My 9.93 @ 135 was with 600 DA and a stiff crosswind.

[tom s]

When talking pump gas does that include E85?Tom

[RAIV-Z]

Originally Posted by tom s

When talking pump gas does that include E85?Tom

We're running 93.

[Dragncar]

Engine I am doing right now should make it. 91 octane, 11.5-1 CR, High Ports, Victor. 1050 should be back from getting worked any day. Few bells and whistles on her so I expect it to run very well. And do it below 7K.
Just picked up the heads from being milled .030, intake fits nice. Waiting on some .016 x .055 spring steel shim stock for the pistons. I expect to get them in this weekend.
I doubt the engine will be run at max power most of the time. When bracket racing I might run a 850 carb and shift it sooner so its not so hard on the engine.
RPMs kill.

[Mike Davis]

I don't see why it could not be done on pump gas.
My little 433/440 Combo made just shy of 800@ 7200RPM with 11.85 Compression on 100LL. Factory block, 990 crank and 68CC Eheads. Dropping the compression 1.5 points I doubt it would lose 100HP. In fact the old combo was 10.5:1 and still made over 750. Basic block fill to bottom of freeze plugs, deburred and lifter bore brace.

[slowbird]

Real issue is how long will it last and if if detonates on pump gas that'll shorten the life considerably

[taff2]

Why f*ck about with pump gas for racing, add Toluene to increase the octane at the track, it's that simple. You can make any type of race fuel you need with it. I've been told that Toluene can be hard to get in the States, but I buy mine off ebay. Approach a few local chemical companies, tell them you need it for work,cleaning off your tools etc.
I made not far off 600 on a 13-1 comp 400 using 2 bolt studded mains weak 554 block with a mild Crane flat tappet cam and iron heads, over 3 years of 7000rpm runs without a hitch.

[steve25]

Xs 2 with post 10!

And to add to that especially with enough runs if the Crank is balanced to every day grocery getter + or - 1/4 ounce at 3 inches and not the far better high rpm race build spec of + or - 1/4 ounce at 1 inch!!

[Mike S]

I will basically have the same combination but lowering the comp. one point. Figured I would increase intake cfm and a more aggressive ramp on the cam to make up for the loss in compression.
Right now I have 12-1 with 180psi of cranking comp.

I want to use it on the street a lot more without worrying of getting race gas. I still want to run the 10.0 index races once a month.

[Vengeance Race Engines]

Originally Posted by Mike S

Want to know if it is possible to make 700hp on pump gas with a factory block.

Yes.

[GTOGEORGE]

Seems to me I could have a short fuse......so why take a chance!



GTO George

[Scott65]

Originally Posted by Mike S

I will basically have the same combination but lowering the comp. one point. Figured I would increase intake cfm and a more aggressive ramp on the cam to make up for the loss in compression.
Right now I have 12-1 with 180psi of cranking comp.

I want to use it on the street a lot more without worrying of getting race gas. I still want to run the 10.0 index races once a month.

Have you considered E85? Tom asked earlier, but I never noticed a response to it... Don't know the availability in your area. Its plentiful here.

[Vengeance Race Engines]

Originally Posted by GTOGEORGE

Seems to me I could have a short fuse......so why take a chance!



GTO George

Based on what?

[GTOGEORGE]

Originally Posted by Vengeance Race Engines

Based on what?

Oh heck, it’s just me. I have a different opinion about a factory block. 700 plus hp takes some pretty good parts that cost decent money. Block could be the weak link..... JMO.

GTO George

[Vengeance Race Engines]

Originally Posted by GTOGEORGE

Oh heck, it’s just me. I have a different opinion about a factory block. 700 plus hp takes some pretty good parts that cost decent money. Block could be the weak link..... JMO.

GTO George

All good. Just thought you had some insight as to why, or if it was just an opinion based on a generalized number. I also don't feel it's the price of the parts that mean it'll make power, but more about the design of the combination. You'd be surprised what can, and has, made that power and more without expensive parts.

[slowbird]

Originally Posted by Vengeance Race Engines

All good. Just thought you had some insight as to why, or if it was just an opinion based on a generalized number. I also don't feel it's the price of the parts that mean it'll make power, but more about the design of the combination. You'd be surprised what can, and has, made that power and more without expensive parts.

I might be wrong, but imo to some extent the price of the parts determines how long it last not how much it'll make.