383 Heads?

[68chargerr]

I am looking at having a 383 engine rebuilt for my 68 charger. Non Numbers matching. I have the stamp # off the heads as 2406516 which is a 383 1964-67 according to my research. The Intake is 2.08 and exhaust is 1.60. I see also that if I had a 2843906 or 383 1968-1970 head the intake is the same but the exhaust is 1.74.

My question is how much difference does this make as far as performance? Can my heads be altered to the same as a 68-70 head? If you were doing a 383 what would you have done to the heads? looking for around 400hp as a final result.

Thanks alot

 

[69 Runner]

The 1.60 exhaust valves and slightly smaller runners will kill you on the top end with a 383. They love to make power to 7000 when properly built, and you won't do it with a 516 that is stock. A 906, 346, 452 on the other hand will get it done.

Just get any of those, have hard seats and bronze guides installed, blend the bowls, and gasket match them i (if you want) and they will get you there.....depending on compression, cam, intake, and carb of course

 

[khryslerkid]

I installed a pair of 906 heads on a stock bottom end 383 once. Used a mild crowler cam and a set of headers. Wow what a difference! Have fun. Those 383's really spin up quick when you let them breath...

 

[Meep-Meep]

The 516's are the early closed chamber heads, and like you found out they have the smaller exhaust valves. They also have a flat intake floor similar to the later unleaded heads (71 and newer 346, 452, etc..). The closed chamber will give you a bit more compression while providing some valuable quench in the cylinder, and in my opinion that will be an improvement over the unleaded heads just from the compression increase alone. You will need to have the larger 1.74" exhaust valve installed and while you're at it have hard seats installed as well. The aforementioned bowl blending, etc.. is a must as well as a good valve job. I have been running the 67 915 heads on all my stuff for years and they work great. My current 440 has big valve 915's and it pulls like a freight train!

Note: 915's have a rounded short side radius just like the 906's and as a result I believe they wet flow better than the flat floor port heads. The 915 head incorporates the best features of two head designs into one nice package, but unfortunately it's a one year only head - maybe two - and they are a bit hard to find.

It's been a while since I built and run a 383 but mid 13 sec 1/4's are not too hard to do if set up properly.

A quick recipe:

As much compression as your fuel allows
270-280 deg cam on a 110-112 LC. 108 works well too but will like it better with deep gears.
650-700 CFM carb
Torker or Performer RPM. The RPM wasn't around when I had my 383 but from what I understand it's a great intake and could very well out perform the classic Torker because of the 180 deg separation and general free flow.
1-7/8" headers.
3.55-4.10 gears
11" converter with about 2400 RPM stall - just not too loose!

 

[Deleted member 214]

I had a set of the early 1.60 exhaust heads fitted with the larger 1.74 valves for my old 383. Poor man's 915s.

 

[68chargerr]

What if I had a set of heads stamped 2406518? according to my finding these are from a 64 426 max wedge, will those even go on a 383? I see they have an even bigger exhaust valve

 

[Meep-Meep]

Max Wedge heads have 1.88" exhaust valves and those will require the cylinder bore to be notched for clearance. Also the ports are much bigger (taller intake) so you will need to customize an intake to fit. Best bet is to use your 516's (poor man's 915's like Greg said) or one of the other standard B engine heads mentioned above.

Sell the Max Wedge heads to fund your rebuild! 64 Max Wedge stuff is hard to find and expensive.