GT40P / GT40 Head Porting (Exhaust Guide Help)

[331TwistedWedge]

Ive been porting on these GT40P Heads for the past 2 weeks, im exhausted :lol: get it? ... lol ... see im going nuts ...

anyway, just some blending of the bowl ... valve guides trimmed down and unshrouded the valves ... i was looking to ramp those low lift numbers up quickly and hoping for 210-215 cfm's at .500 ...

i didnt want to get away from the size of the ports, they are straight to the valve and didnt want to slow the air down ... seems like this is why the head works so well ...

to anyone who's ever ported the gt40p's ~ how far can i go on the roof of the exhaust port, without breaking through to a water jacket? ... ive put a nice slant to the valve guides, but im afraid to treat them like the intake side ... ive read its easy to break through?

any help or pics that you guys can post? ... any flow numbers from some home port jobs that you've done??? ... i would love to see those ...

[331TwistedWedge]

Exhaust guide pics ... this is as far as ive taken it, i would love to go "a lot" further ... any thoughts?

[331TwistedWedge]

here are a few pics of the intake side ... very easy to work with, i wasnt worried about breaking through the guides ... the first 2 were after port work, the last is untouched ...

[331TwistedWedge]

here is some work in the chambers ... the first pic is where i unshrouded both valves, 2nd pic is stock ...

[331TwistedWedge]

ok you head porters, give me some feed back before these are off to get milled ... trying to bump a little compression ... its going in a 3850 lb 1995 convertible mustang ...

[331TwistedWedge]

i didnt just pick a die grinder up and hack away, i must have read countless hours from various sites on how to attack this ... these were my 2nd set of heads that ive done ... my first set was around 6 years ago ... took a few to get back into the flow of things ...

[Jeff88coupe]

Do a search on the corral windsor forum for "gt40p porting". There use to be a huge thread on there with alot of good info. I ran a set of ported gt40p heads on a stock 302 shortblock with a mild custom cam (.513 lift), gt40 intake with ported lower. It put down 298rwhp/320rwtq with just a stock computer (no tune or chip). I used a fms extender to get around the stock rev limiter....I shifted it at 5800. I think that set of ported heads flowed ~225int/190ext at .600".

[331TwistedWedge]

Do a search on the corral windsor forum for "gt40p porting". There use to be a huge thread on there with alot of good info. I ran a set of ported gt40p heads on a stock 302 shortblock with a mild custom cam (.513 lift), gt40 intake with ported lower. It put down 298rwhp/320rwtq with just a stock computer (no tune or chip). I used a fms extender to get around the stock rev limiter....I shifted it at 5800. I think that set of ported heads flowed ~225int/190ext at .600".

i searched about everywhere looking for info ... found some useful pieces on the corral ... found a nice "DIY" porting gt40p website, other sites about pinch points and the dynamics of air flow / venturi effects ... lol ...

those are great flow numbers jeff from a set of pheads ... 225, is nice ... did neil do those?

[kennebellcobra]

Ricky...Ricky...Ricky...everyone knows you can't home port heads.lol

Just do them like the pics of mine I sent you and if you go through use jb weld then duct tape. Ha Ha

[331TwistedWedge]

Ricky...Ricky...Ricky...everyone knows you can't home port heads.lol

Just do them like the pics of mine I sent you and if you go through use jb weld then duct tape. Ha Ha

well i recall you porting some trick flow twisted wedge heads like mine ... .294 on the intake side, that tells me home porting is possible ... :bigthumb ... hell foxlake charges $1300 and they barely out flow yours ...

i have jb weld on hand :lol:

ive spent around 30 hours on them, maybe im done? ... mill and assemble them, then call it a day ...

[Jeff88coupe]

Yes..Neil ported my P heads....he then later ported my AFR 185's.

[Jeff88coupe]

I think I have some pic's of my ported gt40p ports somewhere...gotta find them for ya

[331TwistedWedge]

Yes..Neil ported my P heads....he then later ported my AFR 185's.

does anyone around here have a flow bench and is reasonable? ... im just curious if all that effort was worth it ...

[Jeff88coupe]

BES is the only shop around that I know of that has a flowbench....reasonable? that's up to you.

I can't find any pictures of my old ported p head's ports...just my afr's. I think I probably lost them a few computers ago.

Ricky...post this question and pic's up on hardcore50's board...there are a few head porter guys that visit over there.

[331TwistedWedge]

BES is the only shop around that I know of that has a flowbench....reasonable? that's up to you.

I can't find any pictures of my old ported p head's ports...just my afr's. I think I probably lost them a few computers ago.

Ricky...post this question and pic's up on hardcore50's board...there are a few head porter guys that visit over there.

im on hardcore right now ... lol ... just browsing ...

[Adam@S&MMotorsports]

Ricky Performance Engineering also has a flow bench. I might be able to call in a favor for you...

[331TwistedWedge]

Ricky Performance Engineering also has a flow bench. I might be able to call in a favor for you...

that would be killer ... i would love to see the flow numbers, versus waiting on dyno numbers ... the heads are done and ready for milling ... let me know about the flow bench ...

thanks ............ :bigthumb

[Adam@S&MMotorsports]

Call me tomorrow

[1992MustangDW]

here is some work in the chambers ... the first pic is where i unshrouded both valves, 2nd pic is stock ...

This might be a dumb qustion but could you tell me what you acually did here?

[331TwistedWedge]

This might be a dumb qustion but could you tell me what you acually did here?

if you look to the side of the valves, there is more room on both outer sides ... this is valve relieving or unshrouding ... it allows air in from all sides, not just 75% of the valve ... if done right, it was worth 8cfms up top ... well worth the effort to do ...

overall i just blended/contoured rough ridges in the bowl area and took out the valve guides ... then polished ...

im milling to bump compression a bit, i probably lost a few cc's when removing metal in the chambers ...

[Stangman]

I'd love to do this to both sets I have... but I dont have the patience... I'd rather pay someone a few bucks

[1992MustangDW]

ok I can see that now, looks like a lot of work

[331TwistedWedge]

I'd love to do this to both sets I have... but I dont have the patience... I'd rather pay someone a few bucks


ok I can see that now, looks like a lot of work

man, you have no idea ... 35 plus hours, it gets to you ... you should see shannon's ported gt40's, he went further than me ~ they look nice ...

i say this, if you can get 20 rwhp from a nice port job and milling ~ i think its worth it ... its practically winter anyway, get the die grinder out and go at it ... just read, read and read about it first ... lots of good sites out there :bigthumb

[1992MustangDW]

would you mind posting up some sites on some good techniques?

[331TwistedWedge]

pm sent ...