Welcome, Guest. Please login or register.
May 28, 2017, 12:29:54 pm

Login with username, password and session length
Director PLEASE!!!!
Add your location information to your personal profile. Thanx!
433491 Posts in 37081 Topics by 9458 Members
Latest Member: Rich351
Search: Advanced search
Advertiser Inquiries
+ SBFTECH.com Experienced Small Block Ford Tech
|-+ General Tech
| |-+ General Tech
| | |-+ GT-40 head porting, a compilation with a bunch of pics and measurements
0 Members and 1 Guest are viewing this topic. « previous next »
Pages: 1 ... 4 5 [6] Go Down Print
Author Topic: GT-40 head porting, a compilation with a bunch of pics and measurements  (Read 42710 times)
David Claflin
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 7849


Location: Redneck Riviera (Ft Walton Beach Florida)

« Reply #75 on: April 25, 2015, 05:30:07 pm »

I was putting springs on the heads that are the most heavily ported and run into a rather odd issue, which I should be accustomed to by now
I'm setting up the comp bee hive springs to work with  comp lobes that have .570 and .563 on the intake and exhaust with 1.6 scorpion rockers. I got one head done using a .050 spring cup and a .060 shim under the intake and a .015 shim under the exhaust. I started to do the other head and just thought I'd check the height to make sure they were the same as the first head.  Turns out I only needed a .050 spring cup under the intake and no shim at all under the exhaust.
I put a level across the valve cover rail and measured to the spring seat and it was actually different. The heights to the valve seal machine was the same, but the spring seat was deeper on one head.
One head of this pair is a replacement I got somewhere as managed to put a hole in the exhaust port roof initially, the replacement head does not have the hole drilled for the air port. They both have the same marking otherwise. Just thought I'd share, it never hurts to double check, especially if you're  using third hand junk. 
Logged

1990 Red LX, 306, 75MM, ported gt40's, Holley SMII, accufab longtubes, 3" exhaust, 4.10's, 318RWHP/316RWTQ
1985 LTD LX 302, ported TW's, XE-264 cam, ported Holley SMII, 75MM-R TB, MAC 1 3/4" longtubes, 4R70W, mach 1 brakes
1988 GT long term project
David Claflin
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 7849


Location: Redneck Riviera (Ft Walton Beach Florida)

« Reply #76 on: June 03, 2016, 05:22:48 pm »

Just to provide some more info on this. I had picked up another set of heads at the junkyard, I opened up the bowls like the others, but not as aggressively, did the exhaust ports, and opened up the intake port height to match the ported explorer intake. I put these on the 94 cobra, 75MM TB, genuine fox cobra upper with some work done, ported lower,  stock HO cam, with 1.7s, heads were milled .020, longtube mac 1 5/8 headers, 3" VRS X-pipe, 3" mac cat back with pypes race pro mufflers. We put this on the dyno last Friday, it made 319/340.

My LX with a ported holley SMII intake, 80MM-R TB, more heavily ported GT40 heads, milled heads, B cam , with 1.7s, accufab longtubes, VRS 3"X, 3 catback with ultraflows made 321/308. I had my street tires on the back which consist of 275/60-15 tires on a 15x10 steel wheel which might have affected it some.


* Gt40 exhaust.jpg (6791.89 KB, 5312x2988 - viewed 154 times.)
Logged

1990 Red LX, 306, 75MM, ported gt40's, Holley SMII, accufab longtubes, 3" exhaust, 4.10's, 318RWHP/316RWTQ
1985 LTD LX 302, ported TW's, XE-264 cam, ported Holley SMII, 75MM-R TB, MAC 1 3/4" longtubes, 4R70W, mach 1 brakes
1988 GT long term project
Outlaw Bill
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 4752


Location: Canton, Michigan

« Reply #77 on: June 04, 2016, 07:00:03 pm »

Your results are not surprising since the B cam is only 10hp or so better over the stock camshaft but gives up some torque many times.
Logged

www.TeamZmotorsports.net

TeamZmotorsports 25.2 outlaw drag radial stock suspension 1991 Mustang
Thank You to the following for their help
TeamZmotorsports
Marcella Manifolds
Schoneck Composite
Ultimate Converter Concepts


"Stupid is as stupid does", "You can't fix stupid"
"Common sense is not common"
David Claflin
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 7849


Location: Redneck Riviera (Ft Walton Beach Florida)

« Reply #78 on: June 05, 2016, 04:56:43 pm »

Your results are not surprising since the B cam is only 10hp or so better over the stock camshaft but gives up some torque many times.
I wasn't expecting a whole lot of difference, but I intend to go back maybe next month and run it again with the smaller tires (225/60-15s) just to see. I had ran this engine with a ported GT40 lower, and a box upper, with the stock cam and 1.7s, and smaller tires and dumps on it last year and it made something like 316/318. The engine that is in the cobra is fresher, I just put new rings and bearings in it last year. I have to correct the cobra numbers also, looking at my notes it made 311/339, not what I wrote above.
Logged

1990 Red LX, 306, 75MM, ported gt40's, Holley SMII, accufab longtubes, 3" exhaust, 4.10's, 318RWHP/316RWTQ
1985 LTD LX 302, ported TW's, XE-264 cam, ported Holley SMII, 75MM-R TB, MAC 1 3/4" longtubes, 4R70W, mach 1 brakes
1988 GT long term project
bill88stang
6 Banger
**
Offline Offline

Posts: 71

Location: palm coast fla, formerly long island ny

« Reply #79 on: June 07, 2016, 08:09:15 am »

Great info
Logged

1988 mustang gt 351w lots a goodies
1994 Lightning #2020 of 4007. daily driver
David Claflin
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 7849


Location: Redneck Riviera (Ft Walton Beach Florida)

« Reply #80 on: February 04, 2017, 08:40:26 am »

I wasn't expecting a whole lot of difference, but I intend to go back maybe next month and run it again with the smaller tires (225/60-15s) just to see. I had ran this engine with a ported GT40 lower, and a box upper, with the stock cam and 1.7s, and smaller tires and dumps on it last year and it made something like 316/318. The engine that is in the cobra is fresher, I just put new rings and bearings in it last year. I have to correct the cobra numbers also, looking at my notes it made 311/339, not what I wrote above.
Just as a follow up to this I did run the car on the dyno again with the smaller tire/wheel and it made virtually no difference.
Also, wanted to see if anyone had experience in putting larger intake valves in these heads. I've got a set of 1.90 valves from my son's AFR165s, and wondered if it would be a worthwhile addition to these more heavily ported heads.
Logged

1990 Red LX, 306, 75MM, ported gt40's, Holley SMII, accufab longtubes, 3" exhaust, 4.10's, 318RWHP/316RWTQ
1985 LTD LX 302, ported TW's, XE-264 cam, ported Holley SMII, 75MM-R TB, MAC 1 3/4" longtubes, 4R70W, mach 1 brakes
1988 GT long term project
Outlaw Bill
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 4752


Location: Canton, Michigan

« Reply #81 on: February 04, 2017, 06:54:58 pm »

1.900 is largest you want to go, its what I have in my GT-40 experiments. Some have used 1.940 but you better use a standard 45 deg valve job and not get crazy with 90-92% throats. You may see 250 cfm with the 1.900 but it depends on the flow bench. Seems 250 cfm is the wall for iron GT-40's.
Logged

www.TeamZmotorsports.net

TeamZmotorsports 25.2 outlaw drag radial stock suspension 1991 Mustang
Thank You to the following for their help
TeamZmotorsports
Marcella Manifolds
Schoneck Composite
Ultimate Converter Concepts


"Stupid is as stupid does", "You can't fix stupid"
"Common sense is not common"
David Claflin
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 7849


Location: Redneck Riviera (Ft Walton Beach Florida)

« Reply #82 on: February 05, 2017, 09:40:36 pm »

1.900 is largest you want to go, its what I have in my GT-40 experiments. Some have used 1.940 but you better use a standard 45 deg valve job and not get crazy with 90-92% throats. You may see 250 cfm with the 1.900 but it depends on the flow bench. Seems 250 cfm is the wall for iron GT-40's.
Is it the bowl, throat or chamber size that really limits the valve size?
Logged

1990 Red LX, 306, 75MM, ported gt40's, Holley SMII, accufab longtubes, 3" exhaust, 4.10's, 318RWHP/316RWTQ
1985 LTD LX 302, ported TW's, XE-264 cam, ported Holley SMII, 75MM-R TB, MAC 1 3/4" longtubes, 4R70W, mach 1 brakes
1988 GT long term project
Outlaw Bill
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 4752


Location: Canton, Michigan

« Reply #83 on: February 06, 2017, 09:33:09 pm »

1.900 is largest you want to go, its what I have in my GT-40 experiments. Some have used 1.940 but you better use a standard 45 deg valve job and not get crazy with 90-92% throats. You may see 250 cfm with the 1.900 but it depends on the flow bench. Seems 250 cfm is the wall for iron GT-40's.
Is it the bowl, throat or chamber size that really limits the valve size?

Throat and bowl, gets thin and water is all round that area.
Logged

www.TeamZmotorsports.net

TeamZmotorsports 25.2 outlaw drag radial stock suspension 1991 Mustang
Thank You to the following for their help
TeamZmotorsports
Marcella Manifolds
Schoneck Composite
Ultimate Converter Concepts


"Stupid is as stupid does", "You can't fix stupid"
"Common sense is not common"
David Claflin
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 7849


Location: Redneck Riviera (Ft Walton Beach Florida)

« Reply #84 on: February 06, 2017, 09:45:39 pm »

OK, thanks, I'll leave them alone and run the stock valves. These are going on an 86 short block I got from The Chad anyway, so the smaller valve might be more ideal in this application anyway.
Logged

1990 Red LX, 306, 75MM, ported gt40's, Holley SMII, accufab longtubes, 3" exhaust, 4.10's, 318RWHP/316RWTQ
1985 LTD LX 302, ported TW's, XE-264 cam, ported Holley SMII, 75MM-R TB, MAC 1 3/4" longtubes, 4R70W, mach 1 brakes
1988 GT long term project
Pages: 1 ... 4 5 [6] Go Up Print 
« previous next »
Jump to:  



Powered by MySQL Powered by PHP Valid XHTML 1.0! Valid CSS!
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines



408 Stroker