Holley 500 on 604

[weasel27]

Anybody ever ran holley 500 2 barrel on 604 if so how did it do/compare to the 650? Any info/help on this? Local track made a rule change and just trying to figure out what way to go.Thanks

[Matt49]

Anybody ever ran holley 500 2 barrel on 604 if so how did it do/compare to the 650? Any info/help on this? Local track made a rule change and just trying to figure out what way to go.Thanks

I'd await a good response from Hibbard or somebody that is an expert on crate motors but I think that's too small. The math tells us that you probably wouldn't pull much past 6000 RPMs. Not enough air. Depends on volumetric efficiency and I'm not exactly sure what the VE of 604 actually is but I don't think 500 CFM is going to cut it.

[weasel27]

Ok thanks we are looking for any kinda of help/tips on this. We have steel head 358 we run the 500 on and we turn it about 68 just figured we could do it with the 604 too

[weasel27]

We are gonna run it against the 358s that run on the 500s too

[brad hibbard]

Matt is correct in the fact of "by the numbers" it will be lacking over 6000
BUT
we have found that real world racing the 4412 2 barrel (500) can be nearly as good as a 4 barrel

I do say "nearly" because it is lacking on those last few digits of top end power, however it is very driveable through the power band and as we all know drivability and reaction are worth more than peak power numbers

I am not saying that you should run a 2 barrel but if you HAVE to ---to meet the rules chances are it will be OK

spacer/adapter is key and air cleaner bases make a substantial difference also

Brad

https://www.race-1.com

[weasel27]

Thanks for help Brad, it was a rule change so we have to run them now. With that being said what spacer/adapter would be the best and what air cleaner base? Do you think the gearing will be the same or should I have to go up or down on points to maintain my rpms? Thanks again

[brad hibbard]

the HVH adapter (SS4412-2AL) will pull the hardest at low end

center it on the intake----some engines respond better in other positions (its adjustable) but we found it best in the center

there is one that did better on the upper end but it suffered on low end ------we strive for acceleration so I would stay with the HVH in most cases but if your on a momentum track with sustained mid to upper rpm let me know and I will get you another number

R2C base for sure unless your permitted to remove the choke housing then that's a different story

brad

https://www.race-1.com

[weasel27]

Ok thanks for the info on what spacer and air filter. What kinda of power difference am I looking at with the 2 barrel?

[brad hibbard]

not as much as most think---

depending on the 4 barrel combination that we are comparing to and the fuel being used----
30 peak tops

and through the racing power range its less

brad

https://www.race-1.com

[brad hibbard]

and don't forget about drivability------
2 barrel carbs are vey drivable and what is it that really wins circletrack races?

still not suggesting that everyone run out and buy a 2 barrel ---just don't be afraid of it if your rules mandate it

brad

https://www.race-1.com