proven 496 power [Archive] - Chevelle Tech

: proven 496 power


fowl69
Mar 1st, 07, 2:55 PM
I have a 496 short block. that I want to use as a spare for my car . or somthing in the future. I plan on using AFR 315 cnc for my heads and a dom 1050 that i have. the short block is a gm mk 4 block and eagle 4340 crank and h b rods . the pistons are srp 12.8 comp looking for the most i can get out of this size engine . looking for a solid roller cam recommendation and any other advise on this build any 496 running the same parts . tell me what you got .

jbird
Mar 1st, 07, 3:45 PM
See the 489 link in my sig below. The cam is an Isky custom grind. R649 intake lobe (.736"/272*), R469 exhaust lobe (.714/280), gound on a 108 LSA. The intake looks a little on the short side@.050", but if you look at the the .100,.200 etc. numbers, you can see it is a pretty aggressive lobe.
If I had it to do again I might go a little shorter on the exhaust lobe, R467 is .714/276. Might make a little more TQ that way. This is with 1.7 rockers.

67RS502
Mar 1st, 07, 4:01 PM
It will like 2 1/8" headers and big exhaust;)

fowl69
Mar 1st, 07, 4:40 PM
wow that is stout . very nice power with that set up

cstraub
Mar 1st, 07, 5:07 PM
14.5 to 1 on Gas
345CC Iron Darts
2 x 4150 950HPs
918HP at 7800 rpm
818/794
274/291
110

jbird
Mar 1st, 07, 5:13 PM
wow that is stout . very nice power with that set up

Thanks, it made 840HP on alcohol by the way.

fowl69
Mar 1st, 07, 8:14 PM
I know that it will be a stretch wondering if you could run somthing like this engine on pump gas mainly to see what you could get away with running at something like the PGD like hot rod mag is putting on .

Wolfplace
Mar 2nd, 07, 12:02 AM
See the 489 link in my sig below. The cam is an Isky custom grind. R469 intake lobe (.736"/272*), R469 exhaust lobe (.714/280), gound on a 108 LSA. The intake looks a little on the short side@.050", but if you look at the the .100,.200 etc. numbers, you can see it is a pretty aggressive lobe.
If I had it to do again I might go a little shorter on the exhaust lobe, R467 is .714/276. Might make a little more TQ that way. This is with 1.7 rockers.
=
Hey Jay,,
How about 649/469 ;)
And if you profile these lobes you will find they are 2-3°'s bigger at .050 than advertised on a rat core.

jbird
Mar 2nd, 07, 9:11 AM
=
Hey Jay,,
How about 649/469 ;)
And if you profile these lobes you will find they are 2-3°'s bigger at .050 than advertised on a rat core.

Duh, your right. R649! It would be a 496, with 649 and 469 lobes.:wacko: Don't know how I got THAT mixed up! LOL. I've had to work very late the last three days, so I'm going to blame it on that! I do have a cam doctor sheet(stack of sheets) on the cam, I'll try to decipher it and see what it shows. This same design is going into a slightly larger engine soon but on a 111 LSA and with a 1.8 rocker on the intake. Should be on the dyno soon. I'll report the results.

jbird
Mar 2nd, 07, 10:31 AM
I know that it will be a stretch wondering if you could run somthing like this engine on pump gas mainly to see what you could get away with running at something like the PGD like hot rod mag is putting on .

Not at 14.3:1. There a many variables to getting max power on pump gas. I couldn't even start to guide you on all of that. Basics are pretty obvious, beyond that I would refer to an experts opinion.

fowl69
Mar 2nd, 07, 8:42 PM
well my engine is at 12.8 so was thinking i could do it . might just forget the street stuff . but thought some were running around this compression on this board on the street.