455 low compression thoughts.........
I am writing to you for advice regarding a 455 rebuild in the far( Hopeully )future.
What would you suggest for cam, compression, piston (cast, forged, hyperueteric...sp?) intake(Stock??) quadrajet carb, for a 455 to run on 87 octane. It has to have a nice spread of power to 4,500 rpm maybe 5,000?, not worry about high octane fuel and
generally not fussy.
I looked at suggrstions at ROP, olds power.com and here. All combinations listed were high compression and not street oriented.
What do you say........any experience?? I asked about Procomp heads since i have "J" but the Edelbrocks would they be beneficial in such a situation??
PS automatic trans and high rear end ratio.....3.08


Thanks
joepenoso
Thanks
joepenoso

 

move to a lower gear ratio to start. how much hp you want? 350 or so? stock motors are usually low compression.......

 

3.08 is a fine gear for an 87 octane street motor. Especially if he is going to use a heavy stock rotating assembly.

I recommend shooting for between 9:1-9.3:1 compression, and keeping the cam tame. Something around 220 intake 226 exhaust @.050" On a 110 . If you go less on the duration, you won't have much "lump" ....anything more, and it'll be becoming too big. I'd buy the ebrocks if you can work them into the budget. Much better start than a J head without getting your hands dirty.
Piston choice will depend on desired final compression ratio, and machine work performed to the deck of the block if needed.
I personally set the rod clearances around .0027", .0035" on the mains, 7 quart pan and a high volume oil pump. Everything else can be stock and it'll probably run 12's

Plus you'll get the added benefit of not having to rev it past 5k.

 

Check out the engine I just built for my convertible...click the convertible build link in my signature. It's a 455 (.040" over) with KB 277's (9.5:1 compression) and an Engle 20-22 cam. Edelbrock performer and "E" heads. It's a great cruiser with a 2.73 rear but could use a 3.42 to be a strong performer.

I think with a 3.08 you would be well into the 13's but I'm skeptical about it running 12's (Sorry J). But, it would still be quick on the street and have great manners.

 

I went 13.1's with my delta with a similar setup. 9.2:1 compression 455/th350. Cam was around 218/226@.050
Car was 3740 with me in it, 3.08 posi, home Ported G heads with a standard 2 angle valve job on the Small valves. I'd imagine the Ebrocks would be an improvement over the irons I was running. I used to shift it and go through the traps at 4500 Stock suspension 1.87 60' on 27x8 hoosier 960's

 

That's pretty impressive for mid nines compression and long gears. Do they run on 87 octane? Are forged pistons beneficial? May use Keith Black Hyperuerethig(SP)? pistons?
Thanks
joepenoso

 

I honestly don't have much experience with anything other than cast pistons. Never needed to go any faster than 12's. I have used speed pro forged flat tops, but that's about it. I don't see you needing anything special for your goal. even if you want spirolocks and a roller cam, The 85-90 307 motors had that technology incorporated into their cast pistons. I can send you pictures if you'd like to see them up close. I personally never had a problem with running the 87 octane at the track, but on the street I usually put in 89 just to be safe with my vacuum advance.