Posted By: LL340Rag
Headers vs. 70 Manifolds - 05/04/09 03:32 PM
I have a 340 w/360 heads final compression about 9.25. What HP gain would you guess by replacing the factory exhaust with a set of headers?
Posted By: MLR426
Re: Headers vs. 70 Manifolds - 05/04/09 03:37 PM
My guess would be 20 hp.
logan426
Posted By: moper
Re: Headers vs. 70 Manifolds - 05/04/09 03:44 PM
More importantly... what camshaft?
Posted By: YO7_A66
Re: Headers vs. 70 Manifolds - 05/04/09 04:13 PM
Over the Winter, I swapped out my 70 HP manifolds for the TTi headers (just headers, no other exhaust changes) in my combo listed below. I am still doing some minor tuning to the carb (IFR changes and jetting) so I have not been able to drive the car as hard as I did before this swap, but so far I am very happy with the results.
The off-idle response (torque) is the best part of the swap so far. The car is very responsive in the low range now and over the weekend I found another bonus. With the HP manifolds, the most my converter would flash too at 60mph in third gear cruise was 3500rpms. Over the weekend I noticed that it is now flashing to 3700rpms at 60mph. The swap definately made a "seat of the pants" difference on the bottom end and the flash rpms show some output change too, but I do not have any track information to pass forward to back this up.
Posted By: patrick
Re: Headers vs. 70 Manifolds - 05/04/09 04:33 PM
depending on cam, 10-30HP and 10-30 lb-ft torque....