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65 396 clone

Old Apr 16, 2011 | 10:07 PM
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Default 65 396 clone

any suggestions on getting more hp for a small amount of money.
i recently purchased a very nice 65 coupe with a 66 chevelle 396/325 hp motor. it now has hooker headers and stock exhaust. i thought about square port heads and matching intake and cam, but it adds up to alot of cash and i dont think the car warrants that type of investment. any suggestions are appreciated.
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Old Apr 17, 2011 | 07:41 AM
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Originally Posted by 63vetteman
any suggestions on getting more hp for a small amount of money.
i recently purchased a very nice 65 coupe with a 66 chevelle 396/325 hp motor. it now has hooker headers and stock exhaust. i thought about square port heads and matching intake and cam, but it adds up to alot of cash and i dont think the car warrants that type of investment. any suggestions are appreciated.
The headers was a step in the right direction, but now the exhaust still has to get out of the stock exhaust system. i would get a system with larger pipes and free flowing mufflers. There are a host of companies out there that makes such systems. Years ago I had a Pontiac T/A that was stock. I replaced the stock exhaust system and without adding headers and got a little more air into the air cleaner and picked up half a second at the track. Mt brother who is a mechanic claims all a engine is is a big air pump. The more air and gas it gets and can illiminate the faster it will go.
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Old Apr 17, 2011 | 07:53 AM
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If you already have headers and the motor is in good condition then I would invest in a 2-1/2 in. exhaust system, better intake and carb and a little warmer camshaft. The 396/325 cam is pretty mild. I think you would find that the rectangular heads won't do you a lot of good on a 396 w/o going through the entire motor in the process.
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Old Apr 17, 2011 | 09:19 AM
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Originally Posted by DansYellow66
If you already have headers and the motor is in good condition then I would invest in a 2-1/2 in. exhaust system, better intake and carb and a little warmer camshaft. The 396/325 cam is pretty mild. I think you would find that the rectangular heads won't do you a lot of good on a 396 w/o going through the entire motor in the process.

Mild is kind for the cam in a 325. I used to own one and it had "no" rumble at all. Idled like a kitten.
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Old Apr 17, 2011 | 09:35 AM
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just make sure if you put a new cam in the motor to put the grove in the rear journal
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Old Apr 17, 2011 | 11:26 AM
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Originally Posted by Nowhere Man
just make sure if you put a new cam in the motor to put the grove in the rear journal
Cam would help a lot! Just make sure the actual compression will work with the one you select! Check archives for why the 66 cam is special.

You did not specify your carb and intake, but be aware of hood clearance if u change

I used the corvette central Magnaflow system w headers; any stock system will need short custom pipes fitted out from the headers, just make sure to use 2 1/2 pipes


Last edited by mikem350; Apr 17, 2011 at 11:30 AM.
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Old Apr 17, 2011 | 08:05 PM
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a set of afr rec port heads, raise the c/ratio, and a good hyd cam would really "wake up" your motor.
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Old Apr 17, 2011 | 08:52 PM
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i had the 325 horse in 1968. besides the cam i believe you need rectangular heads also.
remember that block is 2 bolt truck block. jim
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Old Apr 17, 2011 | 09:48 PM
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A 325hp chevelle engine will be a 2-bolt main but not a tall deck truck block. The cheapest way to add a little horsepepper might be to replace the q-jet with a new or used Holley or Edelbrock 750 with vac advance. The headers you have are already a huge improvement over the stock manifolds on those engines.
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Old Apr 17, 2011 | 10:45 PM
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Lots of good advice here!

I wouldn't think about rectangular port heads.
They would kill a street 396.

The Magnaflows are a great idea, and if you can do a 2 1/2 mandrel bent system to them it would be great.

The big thing is the cam, as already mentioned.
It will be good for power and help avoid pinging.
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Old Apr 18, 2011 | 12:43 PM
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it seems like everyone is confirming what i had suspected! a cam and larger free flowing exhaust will probably help. thanks for the input guys.
im happy to be a part of such a helpful community here.
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