low compression alum head 455

[buick535]

Ok, I'll start this off with a build. We are doing a low compression, 8.5 to 1 455 with alum stg-1 heads and an offy dual quad intake . The goal is to make 500 plus horsepower on regular pump gas . I'm thinking should be no sweat.
I've just been thinking lately with all the 10 to 1 stuff we have been doing with alum heads, a regular gas motor would be a neat deal.
The heads flow 320 plus intake and upper 230's on the exhaust. WHat do you think? Jim Burek

[Adam Whitman]

I think if you have the money to build a stage 2, and you are driving a gas-hog 455, that a few cents extra for premium are not a big deal.

I can run regular in my iron head 10:1 engine up her at 5000 ft, although she doesn't like it a whole lot. I'd think no problem with aluminum.

How much power do you think will be lost by going from 10 to 8.5?
I will guess 15-30 HP, But the low end power will suffer the worst.

Would you be better off using cam selection to allow for the lower octane fuel? That is, since you will need a big cam to get the most out of those heads anyway?

[70 gsconvt]

My engine runs iron heads. I have a true 10.13 to 1 compressin and absolutely no detonation problems. I use 93 octane gas.

I would think with aluminum heads you could easily run 10.5 to 1 and still run pump gas with no problems. I did polish the snot out of the combustion chambers, removed the casting button, and removed casting nub off of piston top to remove any potential "hot spots."

Going down to 8.5 compression will cost you about 40 HP or so, according to my DeskTop Dyno.

[71stage1conv]

I kinda like the idea Jim. Yes premium is available today, but that doesn't mean it will be in a few years, or that the price will not soar compared to regular.:BROW: Anyway, it keeps us thinking.:TH:

[buick535]

Originally posted by 71stage1conv
I kinda like the idea Jim. Yes premium is available today, but that doesn't mean it will be in a few years, or that the price will not soar compared to regular.:BROW: Anyway, it keeps us thinking.:TH:




This engine is being built for a rivy, so with a 26 or gallon tank, 20 cents a gallon can really add up . The idea is if we can still make really good horsepower with low enough compression to run regular gas, why not? I know back in 99 when I did the power tour in my gs, It would have been nice to run the cheaper fuel, that was 800 miles in 2 days. The high compression ( 10 to 1 ) motors have been averaging in the 570 horse range and 600 foot pound range on torque. SO giving up some power is still going to make for a killer street engine. At least that's the plan. Jim Burek

[69GS400s]

Jim ... step into my "dream" and pump it up a bit - on the 87 octane pump gas

....Lets say you use one of the new blocks bored out enough .. but not needing all the special high $$$ stuff like crank and cam, but using Alum. S1 or Bulldog heads

What CI do you think would work and what guestimate would you put the HP/TQ at then ??

Dreaming ... Im thinking of 650/650 motor, 87 octane pump gas, 3.73 gears, VP400 and GearVendor, 6K rpm motor, +20mpg in a Tow&Go SportWagon that'll run 11's with the trailer unbolted

:TH: :YA: .... or :RE: :DOU:

[Adam Whitman]

Originally posted by buick535
This engine is being built for a rivy, so with a 26 or gallon tank, 20 cents a gallon can really add up . The idea is if we can still make really good horsepower with low enough compression to run regular gas, why not? I know back in 99 when I did the power tour in my gs, It would have been nice to run the cheaper fuel, that was 800 miles in 2 days. The high compression ( 10 to 1 ) motors have been averaging in the 570 horse range and 600 foot pound range on torque. SO giving up some power is still going to make for a killer street engine. At least that's the plan. Jim Burek

Some hillbilly told me that's not the real plan. The real plan is to post some fair numbers for the combo and then build the first supercharged 455 Riv in the club. :BROW:

You don't think an aluminum head 455 with 10:1 would run on 87 octane?

[buick535]

Originally posted by 69GS400s
Jim ... step into my "dream" and pump it up a bit - on the 87 octane pump gas

....Lets say you use one of the new blocks bored out enough .. but not needing all the special high $$$ stuff like crank and cam, but using Alum. S1 or Bulldog heads

What CI do you think would work and what guestimate would you put the HP/TQ at then ??

Dreaming ... Im thinking of 650/650 motor, 87 octane pump gas, 3.73 gears, VP400 and GearVendor, 6K rpm motor, +20mpg in a Tow&Go SportWagon that'll run 11's with the trailer unbolted

:TH: :YA: .... or :RE: :DOU:



How ab out something right at 500 inches using the stock crank, Hbeam rods, probably 10.5 or so compression and good heads? Should be no problem.
This is one of several combos I have plans for that I would like to build. This is one of the crate motors I plan on being able to offer. Jim Burek

[alan]

How ab out something right at 500 inches using the stock crank, Hbeam rods, probably 10.5 or so compression and good heads? Should be no problem.
This is one of several combos I have plans for that I would like to build. This is one of the crate motors I plan on being able to offer. Jim Burek

How would this do in a Dually to tow with?

[GKsGS400]

How ab out something right at 500 inches using the stock crank, Hbeam rods, probably 10.5 or so compression and good heads? Should be no problem.
This is one of several combos I have plans for that I would like to build. This is one of the crate motors I plan on being able to offer. Jim Burek


The real questions are "How much?" and "When can I get one?" :T:

[buick535]

How would this do in a Dually to tow with?



Should work better than a 502 rat motor. Jim Burek