tore into a 396 with a friend yesterday afternoon at his garage..it's a customers..has 125 lbs. of cranking compression (low was about 120-high of 130) anyway,it ends up having stock .180 domes with 292 open chamber heads graemlins/sad.gif (low,low compression) and it had a Comp 292H in it graemlins/sad.gif
..and a Tarantula single plane..with 2" headers graemlins/sad.gif
..plus it had an M20 with 3.08's..really exciting to drive :rolleyes:
..what a slug.Anyway,time for the 'ole Crane 272 Energizer,some stock valve springs,a Performer intake and a pair of 1 3/4" primary tube headers.
Makes you wonder how many more there are like that out there at cruise nights and dragstrips :(

I bet he ran his high compression(7-1) motor on race fuel too... graemlins/clonk.gif

Well, at least premium!

it had a pretty lopey idle with that 292H too..sounded like something,thats for sure..til you hit the gas..even with an aggresive timing curve it was still "soft"..it might have been liveable with 3.73's or 4.10's

I had the same head & piston setup with a Comp 270H in my '71. I figured it was at about 8:1, when I tore it down and saw those pistons. It had 150 psi cranking compression. Had decent power with the 4:10s, 14.2 @102. Didn't get the chance to figure the launch out before spinning #1 rod.

great example of a 16 sec bbc...lol

great example of a 16 sec bbc...lol ...but is sure sounded good doing it!!!!

Originally posted by mr 4 speed:

Makes you wonder how many more there are like that out there at cruise nights and dragstrips :( Here's a clue: They're all the guys thinking you're a liar when you tell them you run high 12s with your 2.73 'freeway' gears. :D

Sounds like my first big block. Told the machine shop guy that I wanted 9-1. He sold me a set of flat tops (even though he knew I had 049 heads). Try 7.5-1. But with a LS-6 grind, 4.56 gears and 1-3/4 inch headers it still managed 13.2s. Other 454s ran circles around it, I wish I had team chevelle to have helped me then.

MR4,
Which "292" heads does he have ??? There are 2 for big blocks. One is the 6272292 which shows as an "open chamber" the other is a 3964292 which is 109cc. If the open chamber head is 119cc, it is still 8.25 to one with the .180 dome piston. The 109cc head would be 8.9 to 1, not all that terrible for a pump gas engine.
Also, who is to ay it was "incorrectly" built ... that might have been what they wanted.

Originally posted by BillK:
Also, who is to say it was "incorrectly" built ... that might have been what they wanted. Bill,these heads have large,large combustion chambers..the chamber looks like a 3993818 head (pg# 78 in the 'Ole "How to Hot Rod a BBC")

..and with all due respect,who would want a motor built like that? IMHO and experience,it is built incorrectly. An uninformed gear head that thinks bigger is better? A machinist/engine builder who thought it was a good combo?The "classic" Too big of a cam,not enough compression (read:pathetic compression),single plane intake,2" tube headers,etc.My 4000 lb.,smooth idling tank with 2.73's will walk all over this car at the track,and is more fun to drive on the street,even though this turd motor is backed by a 4 speed..I drove the car,it felt like a warmed over 350,but idled like it was a race car..all the wrong stuff for strong street performance,especially with a big block in a heavy car.I'd be embarassed to even take someone for a ride and lay into it..

I'm embarrassed to say this but it sounds quite like my car.... but not for long.

Aw com'on guys, the fella was CLEARLY going to bolt a little 6-71 on and ran outta dough! Blown lil 396 like that would ROCK!

Shoulda had some big ol 990s on there too! :D

Can you rev a blower motor to 7000 without much drama?? That'd be a gas!

ZZiiiinggg-ziiiiinnng

Originally posted by 427L88:
Aw com'on guys, the fella was CLEARLY going to bolt a little 6-71 on and ran outta dough! Blown lil 396 like that would ROCK! :D

The tired 396 I pulled out of the 70 was only pushing 150 psi cranking compression, but it would run on 89 octane and its best was a 9.0 1/8 mile in the heavy convertible with 3:31 gears. It was still fun to drive but I wont know what parts are in it until teardown. 454 goes in next. Chris what is the lowest octane you can run with the compression you have now? I dont want to have to go over 91 if I can help it. My days of ultra 94 are over.

Too much cam, very wrong intake and 3.08s. I will argue with you about whether it is worth the trouble to go to a set of 1 3/4 headers that in most cases don't fit the head ports.

the dynomax are flared out to match the ports.

My Hedman cermacoats are flared to match the SQUARE exhaust ports on BBC heads. They are the first mass produced that I have seen, to be made that way. Perhaps Hedman makes the Dynomax headers too? Either way, its about time don't you think?
They should look awesome bolted up to my Edelbrock "Roval" 100cc high compressions!

Dave (drptop70SS) I run 92 or 93 octane with my 10.59 to 1 compression 462..no detonation problems either,even with 40* total timing

seems to me like he had it set up for being a mean sounding cruiser that would run on pump gas and have low rpms running down the highway. alot of guys do that. performance isn' what is most important for everybody. several other things i could go into, but i gave you my word i'd be nice. :D

Originally posted by m71:
seems to me like he had it set up for being a mean sounding cruiser that would run on pump gas and have low rpms running down the highway. alot of guys do that. performance isn' what is most important for everybodyI don't have a problem with that..it just wasn't fun to drive :D Only thing that was cool about it was that it sounded good graemlins/thumbsup.gif
It should run much better once we get done installing the 272H Crane,Perfromer intake,and smaller headers.

4 speed, do you know what the LSA and recommended ICL is on that cam (272H)? I am assuming it is the Energizer line. Not mentioned on the spec card on the Crane website...

cheers,
Mike S.

I've always installed this cam straight up or 0 on the crank gear

here's a combo a buddy of mine has had for several years. factory spec 325hp 396, original motor for his 69 Chevelle, it has a Comp 292 magnum cam, Stealth intake, 2" Hookers with i believe the 3" collectors, 3.73 posi, th400 with 3000 stall, 3310 Holley, and it's best ET that i know of is an 8.28 in the 1/8mi and a 13.10 1/4mi. i'm not sure on the compression, it's factory 325hp TRW replacement forged pistons. i'm thinking it's probably only around 9.5 to 1, maybe less? it feels alot stronger than it runs though, and it does sound ALOT meaner than it runs. he was pretty cocky until i edged him out with my dish piston stock bottom end 400sbc. :D man that hurt his feelings. he later got into circle track dirt racing.....gee, i hope i wasn't the cause of that! LOL!

I had an engine given to me a few years ago that the guy said ran terrible in his '77 suburban after he rebuilt it. When I tore it down, it had cast flat top pistons about 1/2 mile in the hole, 76cc 882 truck heads with the 1.72 intake valves (less than 8.5-1 compression for sure), and a gm -962 hydraulic 350hp/350 cam, backed by a stock convertor. Gee, I wonder why it didn't run very well graemlins/clonk.gif

I wonder if that engine was built back in the '80's. I have a huge pile of hot rod mags back from the '70's and '80's, and it seems that is how they built engines back then. You could even buy crate motors from some big names with 8.5 to 9.0-1 compression, and up to a 305 magnum cam. I always wondered how something like that would run.

Go easy on the guy that owns it. Having built many small blocks myself, and it is very easy to get compression out of a 355, I built a 396, .030" over with 10 to 1 Speed Pro forged, domed pistons. I added a 294s solid Comp Cam with 248 duration at .050", stock open chamber heads(781's) with the whole K-kit from Comp Cams, Performer RPM, 800 double pumper, stock long slot rocker arms. To top it all off, I ran a 2 in primary tube from Hooker(because that's the only size they make for my car) and ran 2 1/2" Super Turbos turned down at the rear end. My trans was a 4spd Borg Warner T-10, and a 3.90 12 bolt posi.

As I said before, I never built a big block, but when I built it, I thought I was building a 10 to 1 engine especially since the block had been decked. :rolleyes: When I found out I had a measley 8 to 1 engine with mismatched components I was sick!! The thing ran good, had good vacuum, and would run circles around any small block I ever had, until 5500 rpm. Then it was done. Good street motor. If I had dismal gears and an auto, it would have been a pig. I just wish I know what I know now, and bought the larger domes or a set of closed chamber heads. I think it would have been a night and day difference. But I didn't know about Team Chevelle then, nor did I even have a computer to look up on the internet! :D

We've been nothing but helpful to the guy that owns it..he bought it that way,and wasn't happy with its performance.