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Discussion Starter · #1 ·
I could probably write a book on this engine, but i'll make a long story short. When I first started on the rebuild I had all the parts selected that I was going to use. However the 993 heads I was going to use had a bent valve and a burnt seat. When I ordered my Elgin cam I actually got one size bigger than I was suppose to. I went ahead and used it.
Here is my current combo. 406 with 2 valve relief flat tops, crack free set of rebuilt 624 heads with 1.94 valves, Elgin cam with 480 lift, 292 duration, 109 lc, weiand x-celerator single plane intake with divider plate, Holley 600, headers, HEI, 4 speed and 3.55 gears in my 57 chevy. The engine runs pretty good, but I'm sure it would scream with better parts. I wish I would have went with dished pistons so I could get some vortecs. With the pistons I have it looks like I'm limited to 76cc heads. I'm sure 64cc would be way over 11-1 compression and I would need race fuel. I have a Edelbrock performer intake, but its probably not much better than what I have. After all of my machining my budget shrank and I had to use some 350 parts I already had. I have a 402 big block, I sort of wish I would have used it instead. I'm sure in its stock configuration it would run alot stronger than what I have now. I've only heard maybe 1 or 2 people in my whole life say something positive about 624 heads. It looks like that should be the first thing I should dump. It seems the best heads are usually 64cc. Can this be accomplished on 93 octane and maybe a bigger cam that would bleed off compression?
Thanks for your time,
 

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vortec heads are pretty forgiving of higher compression ratios on pump gas, so i'd say to try a set with the cam you have now and see what happens.
i've known of quite a few motors that internet experts and magazine articles say won't run on 93 octane premium that live a happy life on 87 octane swill.
what you've got can't be any worse than a zero decked 355 with flat top pistons and shim head gaskets under 305 heads and using about the same cam you've got in there now. the machinist said it was close to 11.5:1, and it ran great on 87 octane in a 76 Monza with a 4 speed and 3.08 gears- in fact, it was downright scary hearing that body creak and moan under power, then looking at the door gaps when you got out, but the gaps straightened back out over night...
 

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I have ran 624's on 2 engines and they were a fine head, although i had ported them. one was a 388ci and the other 355ci the intake that ran best was the performer RPM. if you run the regular performer back to back with the RPM you will sell the performer and never run one again

in fact i have turned down 20 dollar ones and will run a ported iron intake before a performer..

Both cars with the 624's were 13 second rides that we shifted at 6500 rpm.
You will be 800 or so rpm down on non ported heads.
The 355 had stock 1.94-1.50's and .030 removed
The 388 had 1.94-1.60's and just a slight surface cleanup
 
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1st gen. Camaro car

I have that 292 cam in my 406 w/ stock type double humps, the big chamfer deep dished pistons, a Q-Jet w/ an old 8004, 1.625" 4-tube long headers and it's soft down low to me.

I also have an M-20, 3.31's and back then 26.5" tall tires. I've had it above 6,000 more than once fine!!

Pulled it to make way for my 496.

pdq67

PS., not the best combination, but it still runs pretty good, imho. I built it way back in the early '80's before I knew much about what makes one run nowadays.

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Discussion Starter · #6 ·
Thanks for the replies. It doesn't sound like I'm in to bad of shape. I do have a 750 edelbrock on the shelf that I plan on trying. I thought the 600 may be small for a 406, but it was brand new so I put it on. I have a set of 291 double humps I considered installing when I was building it, but I thought the comp ratio would be to high. Other than the CP I don't think the 291's would help that much. I heard the 624's actually flow descent for what they are. I guess if I do a head swap it should be at least vortecs or aftermarket.

If I could get a low 14 with this engine in its current state I would be happy. Its in a 57 chevy that weighs 3500 with me in it and it also has a 4 speed with 3.55 gears.
Thanks for your time
 

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Spend some time on the 291's do a little bowl blending and shortside blending , on both intake and exaust ports. Nothing fancy and you will happily run low 14's . If you back off the throttle a little:thumbsup:
 

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I could probably write a book on this engine, but i'll make a long story short. When I first started on the rebuild I had all the parts selected that I was going to use. However the 993 heads I was going to use had a bent valve and a burnt seat. When I ordered my Elgin cam I actually got one size bigger than I was suppose to. I went ahead and used it.
Here is my current combo. 406 with 2 valve relief flat tops, crack free set of rebuilt 624 heads with 1.94 valves, Elgin cam with 480 lift, 292 duration, 109 lc, weiand x-celerator single plane intake with divider plate, Holley 600, headers, HEI, 4 speed and 3.55 gears in my 57 chevy. The engine runs pretty good, but I'm sure it would scream with better parts. I wish I would have went with dished pistons so I could get some vortecs. With the pistons I have it looks like I'm limited to 76cc heads. I'm sure 64cc would be way over 11-1 compression and I would need race fuel. I have a Edelbrock performer intake, but its probably not much better than what I have. After all of my machining my budget shrank and I had to use some 350 parts I already had. I have a 402 big block, I sort of wish I would have used it instead. I'm sure in its stock configuration it would run alot stronger than what I have now. I've only heard maybe 1 or 2 people in my whole life say something positive about 624 heads. It looks like that should be the first thing I should dump. It seems the best heads are usually 64cc. Can this be accomplished on 93 octane and maybe a bigger cam that would bleed off compression?
Thanks for your time,
No more screwed up that our Race Car combo

-80 camaro 2,780 pounds race weight
- 406 .030" over with KB hyper flat tops with two valve reliefs, with our heads, deck and gasket compression is 11.5:1
- 283 heads, bowl ported, larger valve installed, no runner work, cut for 1.46" valve springs, milled to .015"
- Crane solid lift cam 256/264 @.050 .545/.563 105° lobe center
- 850 BG annular carburetor
- Powerglide with ATI brake and 4,500rpm ATI Treemaster
- 12 bolt rear with 4.88 gears

Best pass thus far is 10.436 @ 127.4mph @ 6,500rpm past the lights with 6,000rpm shifts
 

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Butch,

You are too far off into hi-po to help here BUT I'm sure glad you posted b/c guy's need to think about max as well as street, imho.

We gotta get together and down a few cool ones!

pdq67
You can watch me run IHRA Summit Pro Am Hot Rod 10.90 Index class next season if everything stays as planned :D

We may run the Camaro in Super Rod which is a 9.90 index, The 505cid for the Camaro should be capable of running 9.0-9.40's so if we back off the tune up we should be able to run 9.90 index with the Camaro, If not we can put together a 327 with the NHRA/IHRA Super Stock legal Crank, Rods and Pistons and heads {$5,500 for the heads}
 

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I got my first 79 Camaro (3850#w/driver) into the mid 13's @ 101 mph using the factory dished piston 350 shortblock, steel shim head gaskets, 624 casting 1.94/1.50 heads with nothing more than a .030" cut and Z/28 springs installed, Speed Pro 300 duration/.436 lift hyd cam, Weiand Expert single plane, 650 double pumper and open headers. (saginaw 4 speed/4.10s on BFG 235 radial T/As, so don't sell your heads too short. Yes there are better options, but so long as you don't overheat those heads (they are crack prone) they should be good for years.

Once it comes time to change them, you need to establish your piston deck height before choosing heads. If your setup is undecked you can expect around 9.75:1 give or take depending on deck height, head gasket thickness, chamber size, etc.

I would look into the Dart Iron Eagle platinums, 200 cc intake runner, IIRC you can get them with a 72 cc runner.

My first choice would be the AFR 195 eliminators, if your compression worked out to less than 11:1 I believe careful tuning would allow that to work fine on pump premium, and the head change should be worth 50 to 100 HP gain.
 

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Discussion Starter · #12 ·
Thanks again for the replies. I'll keep my heads for now and do some fine tuning and try out my 750 carb. I had a set of 283 power pack heads on a 350 once. The engine ended up developing a knock and so I didn't get to run it very long. It did seem to rev pretty quick.

Butch are you using 283 heads because of the class you run in?
Thanks again
 

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Thanks again for the replies. I'll keep my heads for now and do some fine tuning and try out my 750 carb. I had a set of 283 power pack heads on a 350 once. The engine ended up developing a knock and so I didn't get to run it very long. It did seem to rev pretty quick.

Butch are you using 283 heads because of the class you run in?
Thanks again
It was a friends 9.90-10.0 Camaro and the engine blew up, Car was bought with a roller BB in it, We made some deals and the car is 50/50 now, We have had plans to build a 505cid for a while but in the meantime we found junk laying around the shop and slapped together a junk motor that runs pretty darn good for whats in it - I think there may be $700 in the whole engine, The engine was already bored - We just ordered pistons and rings, new bearings and did up a set of heads we had laying in the back, we even had the cam sitting on the shelf

The car is a bracket car right now
 

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Be wary of the 283 heads, besides the smaller intake valves and smaller ports, the 283 heads (chamber) that I cc'd came in at the 58 cc range, well into the 12:1 range on a 400.

Depends on quench and chamber size, i dont have it in front of me but off the top of my head the chambers were 55.5cc after they were milled, the piston sat in the hole .020-.025" {i remember it was a hair less than .025" because the quench was .063" with a .041" gasket} then we took into account the valve reliefs, the compression was 11.5:1 compression
 
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