Does any one have Thumper gt40p's?

mustang1994bob · Feb 4, 2008

I looked pretty hard and couldn't find anything, I've got a engine im building and I have gt40p's and wanted opinions from people that had thumper port theirs. I know he knows his stuff and he does good work on E7's but this is a different head and the price is kinda high, does anyone have flow numbers? You cant really tell how a head is going to perform just by cfm@.500

BYRDPE · Feb 4, 2008

Don't know about the Ps but he worked some magic on my GT40s.

Roland69 · Feb 4, 2008

I want to get some work on my 40's...

mustang1994bob · Feb 5, 2008

BYRDPE, how much hp/tq?

25thmustang · Feb 5, 2008

GT40Ps can be made to perform hard, and my guess is he knows what he is doing with them. The whole combo will probably dictate what he does, but a well running GT40P combo can and will make 300 to the tires without worry and can and will run deep 12s or better. Your best bet is to go ask thumper about some cars he has worked on in the past, I'm sure he has customer information and performance numbers.

BYRDPE · Feb 5, 2008

25thmustang said:
GT40Ps can be made to perform hard, and my guess is he knows what he is doing with them. The whole combo will probably dictate what he does, but a well running GT40P combo can and will make 300 to the tires without worry and can and will run deep 12s or better. Your best bet is to go ask thumper about some cars he has worked on in the past, I'm sure he has customer information and performance numbers.

You are absolutely correct.
Contact Thumper...great guy to chew the fat with.

mustang1994bob
BYRDPE, how much hp/tq?

I never had it dynoed until yesterday.
Unfortunately, I had it dynoed with the Novi.
I'll post the dyno sheet in a day or so when I pick up the car.
460.9/413.9 RWHP/RWTQ corrected

thumper460 · Feb 9, 2008

The GT40s ROCK!! and when they are worked... They can fly!! LOL

Just me...........................

Thumper

91foxbodygt · Feb 9, 2008

i have gt40ps ported by thumper, no times, no dyno, havent even started the car yet. ill let you know as soon as I install my front suspension, approx 1 month

Topdowncruise · Feb 10, 2008

25thmustang said:
GT40Ps can be made to perform hard, and my guess is he knows what he is doing with them. The whole combo will probably dictate what he does, but a well running GT40P combo can and will make 300 to the tires without worry and can and will run deep 12s or better. Your best bet is to go ask thumper about some cars he has worked on in the past, I'm sure he has customer information and performance numbers.

Let's not raise his expectations too high.Ports are just not big enough especially the exhaust side to get 300 RWP "without worry".It's tough to get past 280RWP with those heads.But they can run great;I'm just not convinced they are the best heads to wring the most HP out of.That's what the AFR's and Trick Flows are for.

Flavadave4 · Feb 10, 2008

Email Mike (thumper460)...great guy to work with.

thumper460 · Mar 7, 2008

Actually... 290 -320 WHP is do able on my ported E7s with STOCK valve size.. the 40's and the P's will allow MORE power ( when ported) then the E7s!! Dont dis the GT heads for power!! they rock!!

Just me.....................................

Thumper

myslo50 · Mar 7, 2008

for some reason i cannot email thumper.so i would like to know how much gt-40 ported cost and whats the flow rating stock/ported. or if anyone can help

2000xp8 · Mar 7, 2008

Topdowncruise said:
Let's not raise his expectations too high.Ports are just not big enough especially the exhaust side to get 300 RWP "without worry".It's tough to get past 280RWP with those heads.But they can run great;I'm just not convinced they are the best heads to wring the most HP out of.That's what the AFR's and Trick Flows are for.

I happen to agree.
As for these days anything is possible, i wouldn't say typical numbers are 300rwhp.

And i don't see future room in gt40p's either, where's if you use TWs or afr's they can be ported to accomadate 331's and 347's.

Figure P's to be valued at $300, then by the time you port, valve job, milling, clean up bowls, add springs, and all the hardware, you are at like a grand.
Throw the xtra $100 in there and just get a better head from the get go.
They will be lighter, produce more power, and can be used on a stroker if need be.

thumper460 · Mar 7, 2008

Zackly... nothing like a new or used set of alum heads!! however.. in the real world where "usually" most will build one engine combo, the "Need to grow" isnt an issue... yes??

Ported GT40Ps will allow over 450 HP n/a vs the AFR that will allow over 550 HP n/a!! Now how many guys are running around with a 450 HP n/a engine?? or how many with a 550+ n/a hp engine?? the realistic world is that. NONE ARE!! would be nice, yes?? but it isnt happening..... SOOOooo..... why not build an engine with the torque and power for what you are GOING to actually be using.. than to build an engine that realistically will have too large of ports and "flow numbers" ?? Just a thought here.. yes??

But then this alum head vs ported Iron heads has been going on for years!! Build what you can afford and what will make you happy. Bigger isnt always better!! no matter what "they " say!! cool??

Just me.......................................

Thumper
( ref: Stan Weiss web page)

mazroth · Mar 8, 2008

Would love to build me a sleeper with some ported P heads, shave off the bars, say they are stock, get a heavily stock ho lower ported by tmoss with a shortened/ported upper that looks stock. Match it with a meter and tb, 24lb injector, maybe even the 19s will work, longtubes, no ac ps smog elec fan etc.
I would be on 300+ at the wheels, with a very healthy torque curve for the street, and it would look stock except not having the accessories. I forgot to mention the custom cam as well!

I know of guys with home ported P heads, carbs/ cobra intake with custom cams running low 12s. If done right, they can be fast.

thumper460 · Mar 8, 2008

We have done a few of the "bars removed" GT40 heads for some circle track cars... fast as hell and fun to watch the tech trying to figure out why that 302 Ford is kick'n so many of those 350 chevys!! Stealth is cool!!

Just me...............................

Thumper

Foxfan88 · Mar 8, 2008

P heads go a long way and can support some power.
if you like to work on stuff yourself. you can grab a set of JY p heads, take them apart and if the valves are alright, get the heads cleaned up, get a valve job and do a little DIY gasket matching and bowl cleanup if you like and you can have a killer set of factory heads for pretty cheap.
the only thing that sucks about them is the plug angle situation.
if the P heads had standard plug angles IMO they would be used alot more than what they are and would be more expensive to buy.

red95gtconvert · Mar 8, 2008

Foxfan88 said:
P heads go a long way and can support some power.
if you like to work on stuff yourself. you can grab a set of JY p heads, take them apart and if the valves are alright, get the heads cleaned up, get a valve job and do a little DIY gasket matching and bowl cleanup if you like and you can have a killer set of factory heads for pretty cheap.
the only thing that sucks about them is the plug angle situation.
if the P heads had standard plug angles IMO they would be used alot more than what they are and would be more expensive to buy.

I just had to get creative with the #7 sparkplug and sparkplug wire. I just used a 90* plug wire and cut away half of a sparkplug socket to tighten that plug up, all of the other fit fine, 15 minutes top to solve the problem. The car runs great with the GT40P's and I have no regrets about using them.

Does any one have Thumper gt40p's?

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