Thinking of building a new engine for my 95 GT

302hobronco · Sep 27, 2023

Richard holdener just put out an interesting video of a 347 short block with E7 heads, stock cam and stock intake.

maillemaker · Sep 27, 2023

Randall Garner said:
I have a 347, did not require any clearancing . Sure that wasnt for a 363 stroker, I see a lot of people talking the gt40 heads. But you still get better gains with a aluminum head with much better flow

It may have been, can't remember.

Yes, I think I will go with aluminum heads like AFR or the like.

maillemaker · Sep 27, 2023

Here is a video about the 347 and you can see the relief notches in the bottom of the cylinder bores:

joemomma · Sep 27, 2023

My 2c: if you're worried about the spend on running premium fuel, maybe it isn't the right time to throw a bunch of money at an engine build? Here in middle TN, 93 is about $1/gal higher than 87. You're talking about $15 on a tank. Maybe get a beater of some sort for a daily then build your engine? I realize that would push the build out a ways, but it might be worth it in the end. That way, you won't have to compromise on what you build.

maillemaker · Sep 27, 2023

joemomma said:
My 2c: if you're worried about the spend on running premium fuel, maybe it isn't the right time to throw a bunch of money at an engine build? Here in middle TN, 93 is about $1/gal higher than 87. You're talking about $15 on a tank. Maybe get a beater of some sort for a daily then build your engine? I realize that would push the build out a ways, but it might be worth it in the end. That way, you won't have to compromise on what you build.

LOL, this is my beater I bought to be my daily driver!

This build will be pushed out a ways - I'm going to drive it until it fails. I'll be building the engine along and along.

I want an engine that will drop in and run with the stock harness and ECM. I don't think it's necessary to build and engine that requires higher than 87 octane gas. Worst case, I just build a stock motor. But I suspect that I can build a low-compression engine with a mild cam and better flowing intake and heads and get an engine to 300 HP or so with regular gas.

The more I look at engine dyno results, it seems like you don't really start to see big HP gains until over 4000 RPM anyway. I seldom hit 4000 RPM.

joemomma · Sep 27, 2023

A junkyard GT40 from an Explorer with a cam and valve spring upgrade will get you there, or pretty dang close to it. And run on 87.

r1ch999999 · Sep 27, 2023

I don't baby it, but I'm not driving like an a-hole either. Stock 5.0, 5spd on 87 with 91k.

joemomma · Sep 28, 2023

I have no idea what kind of mileage I get, my odo hasn't worked in some time.

maillemaker · Sep 28, 2023

joemomma said:
A junkyard GT40 from an Explorer with a cam and valve spring upgrade will get you there, or pretty dang close to it. And run on 87.

I think this is the route I'm going to go now.

This Richard Holdener video says pretty much the same thing:

Stock bottom end, better heads and intake and cam and springs. Should be able to get over 300 HP under 4500 RPM. I suspect this will be "plug and play" with the current ECM. Don't know if I'll need bigger injectors or not.

maillemaker · Sep 28, 2023

Is this what I am looking for?

Foxbody Mustang 5.0 GT40 Explorer Intake Manifold 1986-93 | eBay

Foxbody Mustang 5.0 GT40 Explorer Intake Manifold tapped for sensor. The throttle bracket has been machined off for a cleaner look. Rear water line has been tapped for egr water line. Manifold is an Internal egr with center hole in upper and lower manifold. The 5.0 emblem has been sanded and...

www.ebay.com

joemomma · Sep 28, 2023

maillemaker said:
Is this what I am looking for?

Foxbody Mustang 5.0 GT40 Explorer Intake Manifold 1986-93 | eBay

Foxbody Mustang 5.0 GT40 Explorer Intake Manifold tapped for sensor. The throttle bracket has been machined off for a cleaner look. Rear water line has been tapped for egr water line. Manifold is an Internal egr with center hole in upper and lower manifold. The 5.0 emblem has been sanded and...

www.ebay.com

Looks like it. Things to note: there are two versions (EGR and non-EGR), and you'll need the elbow for the TB. I think you'll need 24# injectors to be safe - the Cobras came with 24s I think. You'll most likely need a tune.

EDIT: Those have gone up quite a bit since I bought mine, but then again, what hasn't. Mine is still sitting on a shelf.

302hobronco · Sep 28, 2023

Factory 19lbs (orange) injectors can handle 300hp easily. Plus you don't need to change your fuel pump like you would to run 24lbs injectors properly.

castine917 · Sep 29, 2023

Fear of premium fuel, 300 horsepower goal and you don't rev over 3,000 makes me suggest a 351 swap.

95opal · Sep 29, 2023

castine917 said:
Fear of premium fuel, 300 horsepower goal and you don't rev over 3,000 makes me suggest a 351 swap.

/\ this

maillemaker · Sep 29, 2023

Will a 351 fit under a stock convertible engine bay brace and hood?

Will the stock ECM drive it?

95opal · Sep 29, 2023

maillemaker said:
Will a 351 fit under a stock convertible engine bay brace and hood?

Will the stock ECM drive it?

Your spending money to add more air and more fuel to make more hp but want a computer that was designed to calculate less of the above to run it?

Fast, cheap, reliable..
pick two.

302hobronco · Sep 29, 2023

Fitment of a 351w under the stock hood is a good question. Vert motor mounts are supposedly lower than coupe mounts. Plus to fit under the hood, I've seen the stock 351w efi lower intake ported to fit the stock 302 upper intake. It isn't pretty, but can work. I doubt the strut brace will clear. Also, you will need a 351w oil pan and pick up that fits fox body platform.

302hobronco · Sep 29, 2023

After thought, the exhaust would need some modification as well to run a 351w

maillemaker · Sep 29, 2023

95opal said:
Your spending money to add more air and more fuel to make more hp but want a computer that was designed to calculate less of the above to run it?

Fast, cheap, reliable..
pick two.

I am not looking for a project that ends up being like plucking a thread from a wool sweater, where one thing leads to another and another and another.

I have to put a new engine in this thing. I'd like to boost some horsepower if possible. I don't want to change the stock wiring, emissions, or anything else if I can help it. I might be ammenable to doing a "tune". If I have to yank the ECM then I presume much of the instrument cluster will quit working as it is driven by the ECM?

My suspicion is right now that I can probably replace the heads, cam, and upper/lower intake to get increased flow and pick up some power without messing too much with anything else.

joemomma · Sep 29, 2023

maillemaker said:
I am not looking for a project that ends up being like plucking a thread from a wool sweater, where one thing leads to another and another and another.

I have to put a new engine in this thing. I'd like to boost some horsepower if possible. I don't want to change the stock wiring, emissions, or anything else if I can help it. I might be ammenable to doing a "tune". If I have to yank the ECM then I presume much of the instrument cluster will quit working as it is driven by the ECM?

My suspicion is right now that I can probably replace the heads, cam, and upper/lower intake to get increased flow and pick up some power without messing too much with anything else.

Sounds like your best bet is a mild HCI build on a 302. Keep the cam mild and you can pick up some good power without having to go crazy on tuning and other parts.