Realistic horespower gain

[7duster4]

Whats a realistic horespower gain for my Duster if I switched to headers? here are my specs.

74 Duster with matching 318 and 904. Both been rebuilt.
318 is 9:1 with a 340 cam and valve springs.
edelbrock performer intake and 600cfm carb.
Heads are basically stock except for a valve job.
But worst of all - stock 318 manifolds exiting into duel exhaust.

Based on what I have read the small block LA engines really benefit from headers. I was thinking about Dougs since they have really good fit minus the tti's price tag. This is just a street car. I would say once a year I take it to test in tune. With the above specs I can only manage low 16's. The car just dosdn't seem to have the power for a good launch but once moving seems to pull good. And I have a 3.21 gear with sure-grip. I would love to dip into the 14's but I would need more than headers to accompolish that. So how bad are the manifolds killing me in power?

Thanks for any input.

 

[Robbie2734]

Whats a realistic horespower gain for my Duster if I switched to headers? here are my specs.

74 Duster with matching 318 and 904. Both been rebuilt.
318 is 9:1 with a 340 cam and valve springs.
edelbrock performer intake and 600cfm carb.
Heads are basically stock except for a valve job.
But worst of all - stock 318 manifolds exiting into duel exhaust.

Based on what I have read the small block LA engines really benefit from headers. I was thinking about Dougs since they have really good fit minus the tti's price tag. This is just a street car. I would say once a year I take it to test in tune. With the above specs I can only manage low 16's. The car just dosdn't seem to have the power for a good launch but once moving seems to pull good. And I have a 3.21 gear with sure-grip. I would love to dip into the 14's but I would need more than headers to accompolish that. So how bad are the manifolds killing me in power?

Thanks for any input.

I would get a decent torque convertor first, then go for the headers. Get the rpm up a little at launch and you should see a big difference in time slips. I have the same problem with my car, but it's mostly street driven amd runs strong but doesn't launch very well. I have a 904 core I want to rebuild and then shop for a 2200-2500 convertor.

 

[johnparts]

I think a good flowing exhaust should be worth 10-15 HP at the tires.

 

[7duster4]

Dosn't sound like 10-15hp is worth the money for a nice set of headers. I was considering Dougs but I was hoping for more gains. I could see spending a couple hundred bucks. But you get what you pay for. Converter would be nice but again you get what you pay for.

 

[dustoff440]

The most I have seen on a dyno with set up similar to yours ranged from 17-22 horsepower which would translate to about 2/10 second. Google header dyno tests small block mopar. Get a 150 horse plate nitrous system for about 300 bucks and take off a second and a half.