big block woes - sort of, not really. i've had my '72 SS since i was 16, and my dad and i rebuilt the original #'s matching 402 that was in it, then i took out a loan and bought my 454. some of you have heard this story - i've told it before... anyways, now i'm a 21 year-old college student, and my dad is a mech. engineer working in sales, so there's not a lot of time for wrenching around the house.

without going off on a tangent, the 454 i bought a few years ago turned out to be a total dud. the guy who built it got numerous things wrong, and long story short, we had it rebuilt by a local shop. this is where the fun starts. the first time the engine was rebuilt, it ran good, and a guy from the shop came over and helped us get it up and running with the new carb. (demon 850 - the engine came with the Holley Commander 950 EFI, which we never were happy with...) anyway, the guy from the shop used a special timing light (not sure what kind) but it was calibrated wrong, and he ended up advancing the timing about 15 degrees too far! :eek: needless to say, when the engine fired up, we could all hear the detonation taking place. the man from the shop insisted the noise was 'valvetrain noise' and my father and i made the mistake of not investigating further. i can't believe we did that. anyways, within 3 days, the engine had grenaded. broken rod bolt, threw the rod, flew around inside, broke the cam, scarred the cylinder, etc.

time for rebuild #2. at least the shop stood by its work, and re-did it for free. we get the car back again and it drives for about a week. one day i'm cruising on the highway, *crunch*crunch*, dead. get a tow to the shop, pull the valve covers off, and the driver side has a rocker arm all twisted to the side, and the pushrod resembles a 'C'. uh oh. turns out it dropped a valve into the cylinder, ruined the piston, screwed up the cylinder wall AGAIN, AND punched a hole in the head!

currently, it's getting rebuilt AGAIN, this time with a new set of well, everything internal. i just hope they cover all their bases this time. i guess the moral of this story is:

if you REALLY want something done right, you should do it yourself...

anyways, here's the specs on the engine:

454 + 60 over (thanks to the latest breakdown)
oval port heads off of my #'s matching 402 (i think they're 049's?)
2.19/1.88 valves
TRW forged rods + SRP forged pistons
10.1:1 compression

Comp304HR (hydraulic roller):
244/244 @ .050" | .612/.612 intake/exhaust
1.7 roller rockers (of course)

Hughes 11" stall (3500)
TH400 w/ GearVendors overdrive
Stock 12 bolt out back w/ 3.90 gears

what else... um...

MSD 6A
Moroso wires
Accel Coil

oh... don't forget the K&N. :D

the shop is giving me a dyno-sim of about 453 hp / 560 lb-ft... the torque seems monstrous, but i dunno. when it drove, i didn't really have time to break it in, much less give it some WOT runs, but it felt real strong down low w/ just normal driving and getting on the highway and whatnot...

what kind of times do you think i should be able to post w/ 453/560, assuming i can hook? with that much torque, i won't really want to beat the 12 bolt up too bad with huge launches, i would think...

Atssa lotta duration off a hyd cam and those gears and compression IMHO. Assume you own the grind, else I think it would ET faster with a bit smaller grind, and a dual pattern to boot. Nevertheless , it should be an easy 11 second ride, if you beat up the 12-bolt that is! smile.gif .

oh, forgot to mention of course the demon 850 and weiand stealth intake i have.

the guy at the shop said that cam matches up well with the stall i have and the heads. he's done some port/polishing as well as the valves.

Yeah, I'm nit-picking, don't think twice about it. Again, easy high 11 second I'd guess, but lets let the seasoned racers here give you a better estimate.

mid to high 12s

It is a nicely matched motor. I am thinking you might make more hp and less tq than he guessed. You didn't state if the heads had any porting done (bowl work helps those heads). I am suprised that a 11inch converter stalls at 3500 (usally takes a 10 converter) but the 3500 stall range should work well. With a good exhaust and it hooks and 60 fts well. My guess is low 12s/high 11s. If you have port work solid 11s.

No offence, but I think it is over cammed. A 304º cam needs about 11:1 to 11.5:1 to work well. With 10.1 you should be using a cam of about 270º to 280º adv duration. With the smaller cam the engine would make a ton more torque and would RPM in the range a BB likes. If you want to run the 304 cam, you should increase the compression. As is, the DCR is 7.18. For best performance, it should be a full ratio higher (8.18). It will still run well as is but it will probably be a soft at lower rpm.

I tend to agree with Pat. In my own personal experience I went from a cam with 85* of overlap to one with 72* of overlap. My car picked up .7 and ~8mph in the 1/4. The old cam was hydraulic roller and the new one is a solid roller with a little more lift. However, I think the additional cylinder pressure was a big part of the performance increase. This is on a 460 (.030 454) with ~10.4:1 compression.

I'll tell you about my home built 461 in my 70 SS Chevelle.

Std lower end with cast flat top pistons.
Heads were 1970 396 semi closed chamber, can't remember the casting #. I did my own bowl work but left the 2.06 and 1.72 valves in place. Manifold was a performer RPM, carb a 750 Vac Holley 3310. Cam was a Comp 280H. Harland Sharp roller rockers, Hooker 2" headers and a home built 3" exh with the Big dynomax turbos and torque tech tailpipes.
Convertor was a B&M 10' Holeshot, 3.55 gears.

On a decent day the car would run 11.9 @ 112 and always got me in trouble with my fav tech guy. Put the air cleaner back on and it ran 12.2.

So if your combo is anywhwere close, you will beat is. A real nice street ride.

Sorry about your woes...that has to suck. Hope you are learning in the process, and after all is said and done, you might wish to look for another machine shop......

Ron