To GT-40 or not...........

[OX1]

Dropped a 331 in my dads fox body LTD, left me with an 89 5.0 HO
I was going to drop in the 70, injected using an 88 SD computer.

I also have these parts "sitting" around

Fully remanufatured GT-40 (not P) heads with upgraded valvesprings.
no name 1.7 pedestal roller rockers
Explorer intake /TB
A9P spare and wiring to upgrade SD harness
Pro-m 76 mm MAF for 19 lb inj
Extra set of flowed and cleaned 19 lb inj

Can't decide if I want to use all the GT-40 stuff or not

Plan is 33's for street and possibly 36 X 12.5 swampers for
"lighter" mud runs out in the pines here or there.
The mud runs are the only reason I can think I would
want the extra power (which I realize would be almost
all top end).

Downsides are I could probably get 800-$1000
for that package to buy some nice 36 radial swampers
and I would need a MA meter, which may be subject to
mud or water in the intake at some point.

Really leaning towards dropping the SD motor in as is,
but don't want to regret not having that added top end power
if I need to spin those 36's up a bit.

Any comments on running mud with 36's and a stock HO motor????

 

[65 mustang]

my 2 cents, gearing would wake up the 36" tires more then the motor.

 

[OX1]

my 2 cents, gearing would wake up the 36" tires more then the motor.

Current motor has what appears to be blowby problems, so motor is being swapped either way. Not too worried about gearing with a T-18...........

 

[JGbronc]

Nothing wrong with a little extra kick, IMO. You don't want to regret it later on for sure.

 

[bax]

anything wrong with putting a carb on the HO and getting it all running. See how all that works. If you like it put the injected stuff on it.

 

[ZOSO]

if you have it and dont need the money do it. Plus you can sell all the HO parts to recoup some of the money.

 

[OX1]

if you have it and dont need the money do it. Plus you can sell all the HO parts to recoup some of the money.

Good point, I guess I would get "something" for an entire top end injected package (minus the harness).
Would have to deduct that from the money I would get for the GT40 package............

anything wrong with putting a carb on the HO and getting it all running. See how all that works. If you like it put the injected stuff on it.

I'm a big believer in that long runner intake and the low/mid range torque it brings, so I wouldn't stay carb either way.

I've seen the dyno numbers and below 3000ish there is almost no gain with GT40/explorer vs E7/HO intake. Was just hoping to get an idea if the typical 30-40 HP added upstairs was really needed with the tires I want to run.

 

[WheelHorse]

Rock it stock for now. When you're ready for that stroker crank upgrade, then do the GT40 stuff.

 

[bmc69]

I've seen the dyno numbers and below 3000ish there is almost no gain with GT40/explorer vs E7/HO intake.

There it is...that's the point I was going to make if you hadn't beaten me to it. And if you can get that much coin for the GT stuff (really??) then it looks like a no-brainer to me.

 

[OX1]

Rock it stock for now. When you're ready for that stroker crank upgrade, then do the GT40 stuff.

I think for now I will. I'll add MA wiring to harness and just not use it.
Saves me a bit of time on swapping heads and intake, since I'm trying to make 50th and have body work, paint, and this motor/EFI all to get done.

There it is...that's the point I was going to make if you hadn't beaten me to it. And if you can get that much coin for the GT stuff (really??) then it looks like a no-brainer to me.

Re-manufactured GT40's (not P's) cost me $750 shipped, so I was hoping to get $500 for just them, add in explr upper/lower/TB/fuel rail, flowed/cleaned 19's, an A9P, brand new Pro-M 76 mm meter, and the 1.7 rollers, I didn't think I was too far off my price..........

 

[duffymahoney]

A mustang speed shop talked me out of the GT40 stuff. He said it could hurt some of my low end and like stated above that the HP gains are in higher rpms.

 

[OX1]

A mustang speed shop talked me out of the GT40 stuff. He said it could hurt some of my low end and like stated above that the HP gains are in higher rpms.

Dyno charts I have seen with stock cam was about + 7-10 HP and pretty much the same torque up to 2800ish, then it jumps considerably. Stock HP 5.0 HO's dynos 185-190 and many are dynoing 260-280 @ the wheels with GT/40's and supporting bolton mods (full exh, shorties, MAF, 1.7's, explr intake/TB, etc...)

 

[FlogginHarvey]

Not sure if it will help but it is a fun read and lots of info. Check out page 30 for a Dyno comparison with a GT40 head vs ...

I was forced to rebuild my original 302 late last year and had a budget to stay under. Went roller 5.0 block, 331, and GT40 heads. The seat of my pants is happy I spent a little extra on some GT40 heads... For better or worse these books helped me negotiate with myself and my "budget build" 331. I just simply ran out of money for high dollar heads...

Enjoy reading:

https://books.google.com/books?id=T...ce=gbs_ge_summary_r&hl=en#v=onepage&q&f=false

And another fun read...if you want to take the time...

http://forum.ellum.ch/Ranger/How To Build Big Inch Ford Small Block.pdf

 

[OX1]

Not sure if it will help but it is a fun read and lots of info. Check out page 30 for a Dyno comparison with a GT40 head vs ...

I was forced to rebuild my original 302 late last year and had a budget to stay under. Went roller 5.0 block, 331, and GT40 heads. The seat of my pants is happy I spent a little extra on some GT40 heads... For better or worse these books helped me negotiate with myself and my "budget build" 331. I just simply ran out of money for high dollar heads...

Enjoy reading:

https://books.google.com/books?id=T...ce=gbs_ge_summary_r&hl=en#v=onepage&q&f=false

And another fun read...if you want to take the time...

http://forum.ellum.ch/Ranger/How To Build Big Inch Ford Small Block.pdf

Thanks for the links, but it wouldn't let me see those pages on the first link unless I buy the book.

I was set on a 331/GT-40/blower/mild cam combo for my dads car, as I wanted a torquer and his AOD will not shift over 5000 anyway (and I was trying to limit power somewhat, since he is in his 80's).

I ended up not using any factory ford style head, as I was not happy with how the pedestal valvetrains set up on any of them (even the new alum GT-40's, as I tried them too). At that time, I was shooting for the best engine I could build, and cost for him was not that much of a factor (and TW170's could be had for $1080 shipped just a few short years ago).

------------------------------------------------

This is an interesting alternative, wonder how just the explorer intake would run with SD??

" In an attempt to answer the original question, I actually have some real world experience with this. Like a couple of people have already said, the Explorer, Cobra and GT40 all share the same lower, which is where almost all of the restriction is in the factory piece. The dyno comparisons I have seen between the three uppers show them all to be pretty much the same +/- 3 hp.

A couple of years back I installed a Cobra intake on a friend's car that was stock except for a fenderwell cold air intake and a pair of welded in Flowmasters. It had been dynoed a month prior and turned 198hp to the rear wheels. After the swap, we took it to another dyno day at the same shop. This time it netted 220 to the rear wheels, but the power curve was much broader and it picked up as much as 28hp in the mid-range.

Short answer: Yes, a GT40-style intake is a worthwhile mod on a basically stock engine"

http://forums.corral.net/forums/5-0...hp-numbers-does-explorer-intake-swap-net.html