head porting questions..........lots (kinda long)

SPEEDYLIFSAVR · Jul 21, 2006

I am not well educated in the realm of porting . I have done searches and done some reading but still have a few questions .

There is a new shop that recently opened up near me that does head work , with it being a new shop I am kind of skeptical and want to be educated a little bit before I just go and drop off my heads .

I recently acquired a nice used set of GT-40P heads . They are still fully assembled . Do I need to disassemble and clean them before dropping them off to be ported ie: remove old gasket material , degrease them , remove rockers , springs and valves?

If I remove the valves do they need to go back into the exact chamber I took them out of or is it ok to put them back at random , should anything be done to the valves themselves? After port work is done is it ok to re-use stock valves ?

Is using a flowbench typical of the porting process before and after to see if gains were achieved or is this something I would need to pay extra for and if so is it worth it?

These heads will be part of a street driven set-up which will include ported explorer intake , TFS stage 1 cam and 1.7rockers .

Also as far as the intake is concerned , the heads should be ported first then the intake to match the heads or doesnt it matter as long as they are ported to the same gasket?

From my research this is what I would like to have done : Gasket match intake and exhaust runners (to what gasket should they be matched?) , cut the EGR bump down , smooth everything out and open up a bit in the runners and the bowls . Does this sound correct and typical of decent port job?

One more thing , when a "valve job" is mentioned is this work that is actually done to the valves or the area of the head where the valves are located?

sorry for so many questions and thanks in advance for your replies!

eagleautosports · Jul 21, 2006

Disassembly may or may not save a little bit of money. That depends on the shop. But remember the "less hands in the pot" thing. They'll want the valves because when porting, there's a certain pattern that is required to show that the seat is properly done. As long as the ports are matched to the gasket you're going to use, that should be ok. You might want better valves that are swirl polished and necked down in the combustion chamber area. This enhances flow. The flowbench help make sure that all the cylinders have the same amount of flow and is worth the extra cost. And a valve job is done on the seat area basically making the corner that the air takes around the edge of the valve easier, all enhancing flow.

cleanLX · Jul 21, 2006

the shop will be better equiped to dissasemble-reassemble the heads, let them do it, that way they can coordinate installed heights as they cut the valves/seats.
since they will need to clean the heads (hot tank) I'd not get too carried away with cleanup, scrape the gaskets off but no need to be clinical about it.
Flow bench is the standard to determine gains, and should be part of the process in porting, being charged extra seems redundant.
Port the heads first, then the intake. I'd not get too concerned with gasket matching as you might get nothing more than a flare out which will create a low pressure area.
with gt40p's i'd not be real concerned with making the runners any larger, just clean them up, and concentrate on a quality valve job, short turn work... aka blending.
valve job should include both cutting the valve and seats. this will assure a good seal when closed, and decent flow over the edge of the valve when open. it is durring this process that installed heights will be set, which will be critical in selecting push rod length. Given the shop will do this, it's not critical the valves go back in the same location, but will be if the heads are dissassembled again in the furure.

MY 02... if going to all the trouble of porting a set of factory iron heads, and having flow data on them, it seems a shame to run a shelf cam designed to work with alum. heads having completely different flow charcateristics.
An additional $200 for a custom cam will make you a much happier camper. If it involves saving for a few additional months, then do so, it'll be well worth it.

I would contact Tom Moss regarding intake port work. He does top notch work and no one in the land can compete with his pricing.

Good luck, sounds like a torque-y build.

head porting questions..........lots (kinda long)

SPEEDYLIFSAVR

eagleautosports

New Member

cleanLX

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head porting questions..........lots (kinda long)

SPEEDYLIFSAVR

eagleautosports

New Member

cleanLX

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