[1967chevelle454]

Ok guys so I'm finally almost ready to finish my 454!
Here's the set-up: Holley 850 mechanical secondary, stealth intake
aluminum heads 2.25 1.88 valves, comp 292H magnum
hypertenic pistons 10.5:1 compression, dimple rods
cast GM crank, hooker headers w/cherry bomb glasspacks

Hoping to make around 550 hp!

[roknroy]

sounds about right. if you have square port heads, you might need alot of converter, to wake up those heads...

[1967chevelle454]

yeah I'm looking at around a 3,200-3,500 stall I think for my car. It's going in a street beast chevelle! Wanting to keep the streetability

[roknroy]

i wouldn't run anything less than a tci super street fighter, 241002, with anti-ballooning plates, which will stall about 3600, 3800 rpm.

[1967chevelle454]

well this is going in a strictly street driven car so i was trying to keep the rpm down

[roknroy]

are the heads square port?

[1967chevelle454]

yeah, but the procomp intake ports are slightly shorter than stock bbc ones. idk why. They are 320cc flow and like 115cc combustion chambers. I'll be running a stock size square port intake manifold though. The car has a 12-bolt with 3.42 gears.

[roknroy]

i appreciate your patience with me, as i've just put together a 9 to 1 454. i'm curious to see what your car's gonna run, i mean that in a good way. i keep being told square ports are too big for pump gas engines below 496. are you sure of your compression? 10.5 might be enough. i'm just trying to go fast for cheap!!

[1967chevelle454]

I'm sure of the compression. It's around 10.5:1. I've matched the pistons and everything to get this ratio. I need the high compression for my 292h magnum cam. It's a .550/.550 292 duration comp cams mill. Cubic inches don't really have anything to do with it. All high performance GM muscle cars had rectangular port heads; 396/375hp; 450hp ls6 etc...
What it comes down to is what your wanting to do with the car. Yes as a general rule you want to stick with oval ports on a street car. I'm going with square ports because i want the extra flow the bigger heads provide; even though it wll be at the higher rpm's. This is going to be a hot street car so I think I'll be alright with a little loss down low.

[roknroy]

i here ya! but you can make 540hp with edelbrock oval port heads, and 9.5 to 1 compression, alot more power than a 454 11 to 1 square port 1970 technoledgy. (i know that was probably under-rated.) beleive me, i want your call to haul the mail, that way i know what i need to do!!!

[roknroy]

i need to pay attention to my spelling....jeeezzzz

[1967chevelle454]

Yes that's true. I went with the rectangular procomp heads for three reasons: 1) they are only 1,000 dollars for a set 2) rectangular port is all they had 3) for my chevelle I'm going for a vintage vibe so I liked the square ports because that's what all the high performance cars had back in the day.
My compression is so high because that's just what my particular cam needs.
The edelbrocks are really good heads and an ok deal but they are still almost 2,000 dollars a set!

[roknroy]

your compression is great for that cam! i wish i had that much! mine is around 9 to 1, i run the comp cams 286h. i'm a firm believer in magnum cams.

[1967chevelle454]

I like that real rump racey idle and running on pump gas. If you can't drive it on the street why bother.

[454C10]

Good luck with your engine. I hope it works out for you.

However, 10.5:1 cr with a 454 and a 292H is a little too much compression ratio. 10:1 would be better. 10.5:1 with a 350 and a 292H would be good but a 454 doesn't take compression ratio as well as a 350. Furthermore, 3.42 gear is a little too mild for a 292H. A 3.73 or 4.11 would better. A 3000 stall should be enough.

Let us know how she drives!

Make sure to use a ZDDP oil additive.