[ponjohn]

Has the casting improved on the aftermarket HO intakes.

[JSchmitz]

I would get a fuel pressure gauge that you can see while driving. Those big Holley fuel bowls can mask fuel delivery problems.

[JSchmitz]

Originally Posted by ponjohn

Has the casting improved on the aftermarket HO intakes.

I had a '71 HO intake years ago. It was a parts counter model. The port alignment was terrible!

[Formulajones]

I currently run the RA IV repro intake on my otherwise bone stock RAIII Formula which is the same thing as the repro HO intake with a different part number cast on it.

I bought mine about 2 years ago so hasn't been that long. I didn't find the port alignment all that bad actually. I knocked off some casting flash in a couple of ports and that was it. Stuck it on the car as an experiment. Didn't slow it down one bit.

https://youtu.be/er1z7PpqsnY

[Cliff R]

The original HO intakes had poor casting/port alignment.

Whoever sent the OEM part over for a sample did NOTHING to straighten things up. So the aftermarket units are off as much as the originals if not a tad more.

It's not a deal breaker, they still work fine and it just takes a little work with a high speed grinder to straighten things up.......Cliff

[mchell]

Originally Posted by OCMDGTO

Aaaaand back on track.....
Short version...12.1@111 w a 1.76 60'
Long version.... 88 degrees, hot as hell, first run trans short shifted 1-2 on its own and still went 12.1. Cooled down, adjusted trans modulator, decent launch, ok shift but not perfect, went 12.11. 60' got a little better, ET/60' improved but mph didn't change. Cliff, I agree, converter is far from optimal. Did stall test 30mph in 3rd and punched it, flashed to 3800. I figured it would stall less w more HP/TQ but maybe the opposite? Hope to get back to the track in a few wks to try again

What track you running at?

What does the full time slip look like?.....330, 1/8 etc..................might show something

Should dip into the 11s with some better air alone...... contrary to popular belief, it ain’t easy slinging 3900+ lbs down the track with a tractor motor and a body shaped like a wide brick...... you’ll get it, keep posting progress

[OCMDGTO]

Crossing the finish line around 4800/5k rpms. Carb is a mechanical secondary DP. Launch is at 1200. Slicks at 20psi, fronts(regular size BFGs) at 35psi. Short burnout, no John Force smoke show. I definitely need to check fuel pressure. Track is US 13 Dragway in Delmar, Delaware.
60' 1.76
330' 5.003
1/8. 7.73@90.12
1/4. 12.10@111

[mchell]

Originally Posted by OCMDGTO

Crossing the finish line around 4800/5k rpms. Carb is a mechanical secondary DP. Launch is at 1200. Slicks at 20psi, fronts(regular size BFGs) at 35psi. Short burnout, no John Force smoke show. I definitely need to check fuel pressure. Track is US 13 Dragway in Delmar, Delaware.
60' 1.76
330' 5.003
1/8. 7.73@90.12
1/4. 12.10@111

20 psi in slicks?........were you dead hooking?

Slip looks about right for what you were running.

Your DA was 2100+ in the heat of the day yesterday......that’ll kill a couple tenths and a few mph

You’ll get it....work on scrubbing the 60’ down first....everything will follow

[Cliff R]

You are running right where my old 455 was at every point and it came off the dyno at 455.4hp/540tq. Mine was just a tad quicker in 60' and 12.0's in the 1/4 mile at 112mph.

Not a lot of slip in the converter, at least not enough to raise an eyebrow over.

I think there is a LOT more in the combination, keep tuning.........Cliff

[JSchmitz]

Originally Posted by Cliff R

It's not a deal breaker, they still work fine and it just takes a little work with a high speed grinder to straighten things up.......Cliff

That's true on one side of the port. The other side would need 1/4" of material welded onto it. I sold it for enough to buy a RPM. I did like the look of the factory AL manifold though.

[JSchmitz]

First of all, I'm depressed now. Looked at my logbook. Last run 7/12. Time slips by. Other priorities.

I've been running 26.0/9.0-15 Hoosier slicks on my car for hundreds of passes. 17psi is the sweet spot for my car. I'd drop the pressure if I were you. Do at least a first to second gear burnout. Play with launch RPM. I leave from about 1200 rpm. But I have a mild stall and 3.23 gears.

[mchell]

A word of warning:

If you’re hitting the burn out box more than a couple times of year AND are running a Th 400, I would AVOID a 1-2 shift in the burnout box.

Especially important with any wheel speed and little load..........just saying from experience

[Cliff R]

"That's true on one side of the port. The other side would need 1/4" of material welded onto it. I sold it for enough to buy a RPM. I did like the look of the factory AL manifold though."

Miss-alignment isn't really a big deal. I dyno'd one and didn't add any material to help it out. It made 10hp LESS than my "modified" iron intake on back to back pulls. We dyno's an RPM next, and it made 4 more HP than the HO intake, that's it. Not really much of a gain considering the 1" taller height and the cobbling often involved with using it........FWIW.......Cliff

[ponjohn]

Originally Posted by Cliff R

"That's true on one side of the port. The other side would need 1/4" of material welded onto it. I sold it for enough to buy a RPM. I did like the look of the factory AL manifold though."

Miss-alignment isn't really a big deal. I dyno'd one and didn't add any material to help it out. It made 10hp LESS than my "modified" iron intake on back to back pulls. We dyno's an RPM next, and it made 4 more HP than the HO intake, that's it. Not really much of a gain considering the 1" taller height and the cobbling often involved with using it........FWIW.......Cliff

Dave at SD charges 150.00 more to port the aftermarket HO intakes because they need so much work.



That is what I asked.

[JSchmitz]

Originally Posted by mchell

A word of warning:

If you’re hitting the burn out box more than a couple times of year AND are running a Th 400, I would AVOID a 1-2 shift in the burnout box.

Especially important with any wheel speed and little load..........just saying from experience

I've heard that a lot of times. I do a 1-2 shift burnout. Have done it for decades with no problem. Maybe I'm just lucky.

[JSchmitz]

Originally Posted by mchell

A word of warning:

If you’re hitting the burn out box more than a couple times of year AND are running a Th 400, I would AVOID a 1-2 shift in the burnout box.

Especially important with any wheel speed and little load..........just saying from experience

I was only running low 12's with 9" slicks though. Maybe with a bigger tire it would trash it.

[Cliff R]

I'm sure Dave does want more money to port an HO intake if you want perfect port alignment to the gaskets and openings in the heads. I'm just saying that with a street engine is really isn't a big player.

WAY back when KRE first introduced their heads we built a 455 to test them. We installed them right out of the box with no port matching. The intake ports were considerably smaller in those heads than the gasket openings, so poor alignment and that's the worst case scenario as you'd think the air comes rushing down the larger runner and slams into the openings in the heads sticking out inside the gaskets.

That engine cranked out a couple more HP/TQ using the same set-up my 455 was using at that time and we opened up the KRE heads to match the stock gasket exactly.

The only real difference in the engines were that mine used heavy Crower rods and TRW pistons with thicker rings. The second 455 we supplied for testing use lighter rods and Ross pistons with the thinner ring packs. There were identical otherwise, even used the same carb and intake to dyno them.

I think back to that testing and realized that a little miss-match at the port openings really isn't a big deal, even when the intake ports are considerably larger than the openings in the heads as they were with that engine.......FWIW.......Cliff

[Formulajones]

Originally Posted by JSchmitz

I've heard that a lot of times. I do a 1-2 shift burnout. Have done it for decades with no problem. Maybe I'm just lucky.

I do the same thing, and use 2nd gear in the box on cars that have a bit of rear gear in them, to get the wheel speed up and smoking sooner.

One car in particular I've been doing that with for more than 30 years on a 400 turbo and it's never been an issue, runs mid 11's at 118 mph.

[Formulajones]

Originally Posted by Cliff R

I'm sure Dave does want more money to port an HO intake if you want perfect port alignment to the gaskets and openings in the heads. I'm just saying that with a street engine is really isn't a big player.

WAY back when KRE first introduced their heads we built a 455 to test them. We installed them right out of the box with no port matching. The intake ports were considerably smaller in those heads than the gasket openings, so poor alignment and that's the worst case scenario as you'd think the air comes rushing down the larger runner and slams into the openings in the heads sticking out inside the gaskets.

That engine cranked out a couple more HP/TQ using the same set-up my 455 was using at that time and we opened up the KRE heads to match the stock gasket exactly.

The only real difference in the engines were that mine used heavy Crower rods and TRW pistons with thicker rings. The second 455 we supplied for testing use lighter rods and Ross pistons with the thinner ring packs. There were identical otherwise, even used the same carb and intake to dyno them.

I think back to that testing and realized that a little miss-match at the port openings really isn't a big deal, even when the intake ports are considerably larger than the openings in the heads as they were with that engine.......FWIW.......Cliff

I'll back this up by saying that the BBC guys have been doing this for decades, putting oval port intakes on square port heads and vice versa. Buddy of mine had a nice running 427 chevelle he drove on the street, ran high 10's at 125 mph, with an iron square port head and a victor jr oval port intake on it. It works. Has something to do with the velocity the smaller oval intake picks up before it enters the square port head, and the port mismatch had no detrimental affects on it. Sort of a different deal, but shows port alignment isn't as critical as people may be led to believe.

[slowbird]

Originally Posted by Formulajones

I do the same thing, and use 2nd gear in the box on cars that have a bit of rear gear in them, to get the wheel speed up and smoking sooner.

One car in particular I've been doing that with for more than 30 years on a 400 turbo and it's never been an issue, runs mid 11's at 118 mph.

Curious, why not high gear?