HO vs gt40 intake @low rpm, any difference?

[BerniniCaCO3]

Hi!

The HO intake is $25 at the scrapyard and readily available.
The gt40 intake is also $25, but is not so readily available: they vanish quick.

I can however buy them at $100-$140 on craigslist.

About the highest I EVER rev the engine is 3500 rpm, which is going 70mph in 3rd gear to pass someone on the highway before going back to overdrive, if the calculator I used was truthful.
So I really don't give a damn about 5000rpm performance.

For my $100+, will I notice any difference between the stock HO and the gt40 intake?
If not, I'll leave it stock HO.

[BerniniCaCO3]

I'm going to be running mildly ported gt40 heads and stock HO cam btw, with stock fuel injection-- for what it's worth.

[91waggin]

If you only care about performance under 3500 RPM, you should probably use the explorer cam, rather than the HO cam. About the intake, IDK.

[1990LTD]

Hi!

The HO intake is $25 at the scrapyard and readily available.
The gt40 intake is also $25, but is not so readily available: they vanish quick.

I can however buy them at $100-$140 on craigslist.

About the highest I EVER rev the engine is 3500 rpm, which is going 70mph in 3rd gear to pass someone on the highway before going back to overdrive, if the calculator I used was truthful.
So I really don't give a damn about 5000rpm performance.

For my $100+, will I notice any difference between the stock HO and the gt40 intake?
If not, I'll leave it stock HO.

don't fuckin pay $100 for a HO intake, I can tell you that much at least. I paid $80 bucks for a HO throttle body/egr spacer and the upper/lower intake manifold with a gasket and that was a ridiculously high price.

[BerniniCaCO3]

no, $100 for the explorer intake
I'm having trouble finding cfm flow rate measurements... but I guess what it would boil down to is this: at 500-3500 rpm, with gt40 heads, and a snorkel inlet, will the stock HO intake (which I have already; paid $40 and that was too much, hahaha) flow at least as much as the engine demands, or will it be a bottleneck? If the HO intake can flow everything the engine needs at 3500rpm, then I don't care about the explorer intake If I'll be starving the engine... then I probably do want to spend the $100.

[1990LTD]

ahhh okay. sorry about that, my bad.

[1980c10]

The expo intake will make more power and torque than the h.o. Everywhere I would be willing the bet plus you already have ported gt40 heads might as well use the intake they come with. Stop worrying about makeing power from idle-3500 and choking your engine it will make plenty I promise just let it breathe. Also if you want flow specs for a exploder intake look up a 93 cobra intake flow numbers they are nearly identical.

My other advice as others said you might want to run a explorer cam. I have never ran one, but I do have a stock h.o. Cam and it comes on like a light switch at 2500. It's not noticable as much in a stang but it's much more noticable with the added weight of our cars.

[johnunit]

The expo intake will make more power and torque than the h.o. Everywhere I would be willing the bet plus you already have ported gt40 heads might as well use the intake they come with. Stop worrying about makeing power from idle-3500 and choking your engine it will make plenty I promise just let it breathe. Also if you want flow specs for a exploder intake look up a 93 cobra intake flow numbers they are nearly identical.

My other advice as others said you might want to run a explorer cam. I have never ran one, but I do have a stock h.o. Cam and it comes on like a light switch at 2500. It's not noticable as much in a stang but it's much more noticable with the added weight of our cars.

Very good advice.

Personally, I think if you're talking parts that came on a Ford from the factory you only have to think about low-end power when considering:
intake Runner length
Cam

That's it. Exhaust can be as big as is reasonably available, GT40 heads can be ported till you break through into the water passages, etc. and you won't really hurt torque down low. These cars were so choked down from the factory that you have to go to serious race parts before you get to the point of "too big" for street/low rpm use.

[1990LTD]

I found a set of E7s..my hunt continues for GT40s..

[gadget73]

Explorer cam is solid power from idle to 4500. Past 4800, it makes absolutely no power. I once got mine to rev to 5200 rpm. It made a lot of noise, no power, and I blew a header gasket for my troubles. HO cams will easily do 5200 rpm in an otherwise identical motor, but they are very much light-switch like at right around 2500 rpm. With a looser torque converter, that doesn't really matter any but its kinda shite with the stock converter.

[BerniniCaCO3]

got it. Yeah, I might want an explorer cam-- if the the engine rev calculators are accurate (and there's no reason they shouldn't be, I could figure it out myself in 5 min if the calculators didn't take just 1min), even passing someone at 75mph in 3rd gear is only 3200 rpm. I don't think I'll ever need to go higher.
Now, is the timing the same? And the mark vii computer should be compatible with an explorer cam? Or would I NEED to go maf?

Second-- anyone have an explorer cam? Boneyard wants $15, but customer service there is nonexistent $15, 5 hrs, cutup hands and cussing and I'll have an explorer camshaft... if someone here pulled an explorer engine and put in an HO camshaft and has it lying around let me know!

[BerniniCaCO3]

hah, speaking of gt40 heads and water passages... I spent tonight cleaning up the valves and valve seats, and noticed a clanging sound inside one of the heads that I picked up at the junkyard last week. I shook it out, and... there's a bit of casting sprue that was knocking around in the coolant passage! Bet that did wonders for cooling :-/ It must've been there since the day the heads were poured and the sand blasted out of the rough casting; there's nothing else it could be-- it's a 2" long, 3/8"D (tapering to a point) bit of corroded rough iron that came out of the freeze plug hole.

[1990LTD]

got it. Yeah, I might want an explorer cam-- if the the engine rev calculators are accurate (and there's no reason they shouldn't be, I could figure it out myself in 5 min if the calculators didn't take just 1min), even passing someone at 75mph in 3rd gear is only 3200 rpm. I don't think I'll ever need to go higher.
Now, is the timing the same? And the mark vii computer should be compatible with an explorer cam? Or would I NEED to go maf?

Second-- anyone have an explorer cam? Boneyard wants $15, but customer service there is nonexistent $15, 5 hrs, cutup hands and cussing and I'll have an explorer camshaft... if someone here pulled an explorer engine and put in an HO camshaft and has it lying around let me know!

some people have been able to keep speed density, some people havent. you really gotta put it together and see if it works with the sd parts to know.

[86VickyLX]

some people have been able to keep speed density, some people havent. you really gotta put it together and see if it works with the sd parts to know.

This. We haven't figured out what the magic answer to the weird popping and backfiring bullshit. Granted, this is with P heads, not sure if GT40s would yield similar results...