Heads and compression ratio
Thread Starter
Burning Brakes
Joined: Nov 2005
Posts: 1,229
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From: Philo Illinois
Heads and compression ratio
I have a stock 73 L-48, and I have found a set of 64cc heads, I know this will give me a higher compression ratio, but what will it be and what kind of horsepower gain can I expect? I guess I should clarifiy a stock L-48. I have added a performer intake and cam, a 600 Holley and headers. Thanks in advance for the info.
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
My 72 350 had a 8.5 CR with stock 75 cc chambers. I rebuilt with Trick Flow's 64 cc chambers. Using a compression ratio calculator, a .035 compressed head gasket I ended up with a 9.7 cr. Also used 12cc, same as stock, dished pistons. If I can find the link for the cr calculator I will post it. Best of luck
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
Well I started out just to do a rebuild...all orignal 109 k Cali car. But it needed bored, crank was marginal.. So I bought a 383 Eagle rotating assembly, new TF heads, new polished alum intake, stewart water pump, all new ARP hardware, comp reto roller cam, new Holley SA carb. Everything was blue printed and the rotating assembly was re-balanced.
The only thing original is the block, oil pan and ram horn exhaust maifolds. I moth balled all the origianl parts: heads, intake, carb, air cleaner, cam, pistons, valve covers, etc.
Best guess I have 400 + HP and TQ
Sounds great, great street manners, runs all the vacuum items, and it is an air car. Cam has 224/230 duration @ 0.050 with 540 550 lift with 1.6 roller rockers. Also went to a 2800 rpm stall convertor and kept the stock 308 rear gears.
Again its a great cruiser with gops of torgue....
The only thing original is the block, oil pan and ram horn exhaust maifolds. I moth balled all the origianl parts: heads, intake, carb, air cleaner, cam, pistons, valve covers, etc.
Best guess I have 400 + HP and TQ
Sounds great, great street manners, runs all the vacuum items, and it is an air car. Cam has 224/230 duration @ 0.050 with 540 550 lift with 1.6 roller rockers. Also went to a 2800 rpm stall convertor and kept the stock 308 rear gears.
Again its a great cruiser with gops of torgue....
Race Director
Joined: Oct 2000
Posts: 15,013
Likes: 79
From: central FL, near the beach.
I have a stock 73 L-48, and I have found a set of 64cc heads, I know this will give me a higher compression ratio, but what will it be and what kind of horsepower gain can I expect? I guess I should clarifiy a stock L-48. I have added a performer intake and cam, a 600 Holley and headers. Thanks in advance for the info.
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
What kind of heads are they? The brand or casting number won't affect your CR, but it will affect airflow and how they bolt up to accessories, etc.
Also, don't forget to put a cam on the shopping list to go with the higher CR. The L-48 cam was nothing to brag about.
Also, don't forget to put a cam on the shopping list to go with the higher CR. The L-48 cam was nothing to brag about.
