Will exhaust porting lessen torque?
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Junior User
Joined: Dec 2005
Posts: 59
Likes: 0
Will exhaust porting lessen torque?
I ground out the thermactor humps and matched the exhaust ports to the manifolds on my D3VE's. However, when I dropped them off at the machine shop for new guides and seats, a guy said my efforts will work against me. I'm trying to make an engine for towing (with torque peak at 2000). Should exhaust port work only be done on high HP, high revving engines? Will my porting compromise low RPM torque? If neccesary I can start over with used D3VE cores fairly cheaply.
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
Likes: 11
From: Exmore, VA
I did one a number of years ago for a wrecker. I used early 460 pistons with the later (79) heads. CR worked out to 9.5:1. I took out the thermactor "humps" for him , this was for a 1986 F350 cab/chassis with a granny low 4 speed. After it was installed, the owner's first big job with it was a loaded step van (probably on the order of 12K), he towed it from dea stop over an overpass nad hit the 45mph speed limit before he topped the overpass. Needless to say the factory 10.5" clutch didn't hold up, we ended up with a 12". My son caught the owner doing burnouts trying to pop a wheelie in the parking lot of his station. Low end torque was not a problem.
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
working on the exhaust side is not going to hurt you expecially on factory heads, if you were hogging out the intake side then yes that could hurt your low end performance, but the exhaust side isn't going to hurt and will most likely help you all the way around. Is there a point were it could hurt you? you bet there is but unless you were getting absolutly crazy with a die grinder, then filling in and reshaping the ports cause you ground into the water jacket and made the port so large that you can't get any velocity at all below 4000rpm then it MIGHT hurt you some.
Sounds like the "expert" works on chebbies and don't know squat about fords don't sweat it your good to go.
Sounds like the "expert" works on chebbies and don't know squat about fords don't sweat it your good to go.
