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Discussion Starter #1
I have a 302 J-code in my '68 that was rebuilt by the previous owner some time ago (maybe 10-15 years ago) and nothing fancy was done, just a 'factory refresh'. The motor runs well decently, it's been reliable thus far and it's pretty peppy (better than I had anticipated). I had originally planned to swap the motor on this car but given the motor does have a matching VIN, I thought it'd be nice to keep it in there and do a more mild build (was originally going to go with forced induction but I don't want to risk the matching block). I don't actually know what's in the motor but plan to do a leakdown, after which I'll see if I need to do any internal work.

What are some mild mods that can be done with a 302 J code and what sort of power and torque can I expect? I don't have a budget in mind but I'm definitely looking to do longtubes, a 3" exhaust with flow-through mufflers. I don't know if an intake will do anything, and I will probably go with a Holley Sniper. Are there any cams that work well naturally aspirated? A nice lope at idle would be big plus to me and I'm not too inclined to swap to roller cams.

Is there anything specific about the Jcode 302s that I should be aware of?

You guys know a lot about these things so if you have specific brands/parts or combos of parts you recommend, that would be very much appreciated! I don't have a set budget in mind but am happy to spend to get more power. Car currently has a C4 auto trans, so I will be looking at the T5 swap as well.

Thanks all!
 

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Discussion Starter #2
Any info on the J code 302 fellas? Just trying to get an idea of how far I can push this motor.
 

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1967 Mustang Convertible
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Well the good thing is you got a good base with the 10:1 compression of the 302. Just throw on a good set of heads (GT40P, AFR 165s, etc.. depending on budget) and a matching cam. Don't need a 3"exhaust. Depending on mods a 2.25-2.5" exhaust will be fine. Also a good intake, Weiland or Edelbrock RPM. You can get easily over 300HP or more depending again on budget.
 

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Discussion Starter #4
Well the good thing is you got a good base with the 10:1 compression of the 302. Just throw on a good set of heads (GT40P, AFR 165s, etc.. depending on budget) and a matching cam. Don't need a 3"exhaust. Depending on mods a 2.25-2.5" exhaust will be fine. Also a good intake, Weiland or Edelbrock RPM. You can get easily over 300HP or more depending again on budget.
Thank you. Are the stock heads complete garbage? I was hoping to keep the original heads but swap a cam (still flat tappet) and then bolt on intake/exhaust. I feel like if I swap the heads, I may as well just build a complete motor and save the matching VIN motor on the side.

If we are talking about forced induction, how much boost or power can the stock J code 302 handle roughly? I know 10:1 is not ideal but what is the risk of breaking something if I am able to put down 300whp with boost instead of N/A? Just trying to get an idea of how tough these motors are. Apologies for all the questions, I'm new to these cars and motors (familiar with 3v 4.6L and up only for mustangs).
 
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