[The Camaro Guy]

What would the stock compression be for a 73 454 with 346236 heads, need to know before I order a cam. Stock pistons, 30 over.

 

[Malibu ss 64]

Advertised as 8.5 in comp but dont think 236 heads came until 75?
If bored 030 are you sure they used oem style pistons? flat, dished or dome?

 

[The Camaro Guy]

Date code 73, H581P domed cast pistons, 2 are cracked due to detonation. Built by PO

 

[71350SS]

Date code 73, H581P domed cast pistons, 2 are cracked due to detonation. Built by PO

I'm not 100% sure but I think a 73 454 would have flat tops as stock pistons.What are you replacing the cracked pistons with,that would determine your new compression ratio then pick the cam you want..

 

[Malibu ss 64]

Date code 73, H581P domed cast pistons, 2 are cracked due to detonation. Built by PO

Is both head and block code 73? Or just the block?
Those pistons arent stock, they have a decent dome. With your heads You might have 10.2-10.5 in Comp but you need to cc the heads, know if block is decked gasket thickness etc to know exactly. Like I answered in you previous thread icon 9919 or h639cp is a better budget choice if you use a cam thats streetfriendly and want to use pumpgas. Around 9.5 in Comp ratio is much better with iron heads with current 10+ in Comp things like just happened is a risk if you use a street friendly cam or if tune is perfect. If you want thinner rings and spend more money SRP 212135 is nice used a set last year.

I think you need to set a realistic hp goal after intended use and budget if your block is ok after the detonation. After that you can get both good cam rand piston recomomendations.
Car, transmission, stall if auto and rear gear will also help+rest of the engine spec intake carb etc.

 

[The Camaro Guy]

Appreciated the feed back. I was planning on using the same profile piston, either cast or forge. The block and heads are matching 73, close date as well. Air Gap intake, 750 Holley VA, HEI, headers, m-20, 3:42 posi, all that is the same as was used. Before I change cams I would like to know the specs, Crane HIT 292-2 NC, know one seems to know, it is in good useable condition.

 

[Malibu ss 64]

Appreciated the feed back. I was planning on using the same profile piston, either cast or forge. The block and heads are matching 73, close date as well. Air Gap intake, 750 Holley VA, HEI, headers, m-20, 3:42 posi, all that is the same as was used. Before I change cams I would like to know the specs, Crane HIT 292-2 NC, know one seems to know, it is in good useable condition.

Ok never heard or seen so early 236 heads?
Maybe Billk has an old crane catalog?
If not put the cam in the block and check it with a degree wheel or maybe a shop close has a camdoctor? Or maybe comp cams the owner of crane can help you of you call them?
I still think its a good idea to lower your comp and still think the piston part nr’s in my earlier posts is a better choice.

 

[shovelrick]

Might want to look at Autotec/Racetec forged pistons, I don't remember the material of each but the Autotec is more street friendly forged alum than the Racetec IIRC and very good pistons and reasonably priced, Wolfplace Mike Lewis is a dealer and who I bought mine from in an entire balanced rotating assembly

 

[68Chevele]

Mine came out to be 7.89 compression with a .039 gasket. With the 360's that had a smaller chamber (116cc) it was 8.2 and the car still ran 11 teens N/A.

 

[1975TypeS-3]

236 heads were produced from 1975 through 1987 - most likely have a 1983 date code heads. Open chamber roughly 121cc