I am dynoing tomorrow! ..Vote on my rwhp.

[5spd GT]

This is not the first time I have seen results like these from a similar swap, to AFR 205's.

It is funny how the volume is less, but the power is substantial in difference. The design of the heads is top-notch.

Anyone that says otherwise is just trying to sale another brand.

Your TQ loss at lower RPM's is likely to be attributed to the camshaft being spec'ed around the old 210's.

 

[Pokageek]

Makes sense 5spd. The long-tubes should make over half as much difference as the heads alone. I am having a real hard time leaving all that power on the table too...

 

[final5-0]

Dude

Get up the charts :Word:

If they were done in such a fashion that I can extrapolate numerical values
from them

Who Knows

You just might find a little side by side comparison

Never can tell

You just might find ... Fame On The Net
for at least 5 nano seconds

Seriously ... if you got numerical values of the pulls
it would save me a lot of work

Grady

 

[str8stang036]

lol

 

[Pokageek]

Can someone help me with the upload? it says the pic is too large! damit.

 

[1slow95]

Here you go!

 

[Pokageek]

YAY!

 

[Pokageek]

Come on guys...wheres the analysis! tapping fingers............................. lol

 

[1slow95]

Well here's mine for a comparison.

 

[Pokageek]

Accufab said shorty headers are literally worthless on my c.i. That's where I think I am leaving most the power on the table down low and higher. the mid-lengths I am getting are what the old 60's muscle cars used at the tracks. Long-tubes are super but for race cars. I am a steeter not track. In fact I may never go to the track.

So I am prolly going to hate scraping and dont want to go to the trouble of cutting out the body although a cool option. I was going to change to long-tube and decided not for the streetability reason and ease of install and my usage of the car. I realize I might be giving up 15rwhp @>5000 but I am ok with that. So if I get better performance 2500 > 5000 I am happy. Although I predict a 425+rwhp #.

p.s. I dont know who said it but put 302/351 parts on a car and get 302/351 c.i. HP. I have a 414 c.i. and need to put 414 c.i. parts on it. I tried the other way and it doesn't work. Something will always be holding you back!

 

[S351Saleen77]

Congrats on hitting 400!!

Low-5.0 is up on you @3k by 60 ft lbs, so do his headers scrape on everything??

Does anyone know of any longtubes that fit good for a 351 block? I was going to use a place out of California that custom makes them and they said I could keep sending them back and they would modify until its right.....sounds like a big hassle!!

 

[S351Saleen77]

I went to the Accufab website and looked at the headers. Are you getting "SPL" stock port location and bolt pattern headers?

This is the problem....you can't get a big tube on with the stock bolt pattern. They have to "Pinch" them at the header flange to get the bolts in.

I'm getting ones that have a "Plate" that bolts to the head with counter sunk bolts, then it has new holes for the header tube to mount to. These holes are much wider than stock so the header tube can be bigger and not "Pinched". This is how Hooker does it on their 2" long tube headers. Anything bigger than 1 5/8" will be pinched....I have seen the Mac shortys that are 1 3/4" and the are pinched at the head big time defeating the whole purpose of a bigger tube header.

 

[Pokageek]

Go Accufab Exhaust and talk to george. Anybody that tells you they are willing to work them is not a negative but a positive. Every car is different. HOWEVER, I would get local shop to tweak them on. No ,mine are not going to be pinched.

 

[Grn92LX]

I have never once scraped my longtubes ever on my street only car. 94-95's shouldn't be much different. Some brands hang lower than others. Longtubes are not for race cars only. You're already down on power from where the combo should be. If you are going to change the exhaust, do it right don't half ass it. Or don't do it at all.

 

[str8stang036]

RC's long tubes fit fairly up high.

 

[Pokageek]

I have never once scraped my longtubes ever on my street only car. 94-95's shouldn't be much different. Some brands hang lower than others. Longtubes are not for race cars only. You're already down on power from where the combo should be. If you are going to change the exhaust, do it right don't half ass it. Or don't do it at all.

Aw Damit...... You're right I think. I do not want to do this twice. Ordered the LT's.

 

[S351Saleen77]

I agree you should get the long tubes! So what ones did you get? Did you get the SPL ones? If so I would love to see some pics of the header where it bolts to the head.

The SPL ones are 1 3/4".
The ones that they say fit any port combo (I guess you just specify) they have in 1 7/8" and 2" tubes. This is what I would want the bigger tubes, 1 3/4" are just the next step up from what you have now 1 5/8"..... I was looking at Hooker 2" LT but have no idea how they fit.

 

[5spd GT]

BBK Longtubes here. They have dragged on occasion.

Just because one person with longtubes does not drag, does not mean everyone will not.

It depends on where you live, drive, and how often.

There is a time, place, engine, etc. for a short tubed header.

I would concentrate more on increasing the o.d. diameter and collector length. The longtube will take care of the collector length, and the diameter is based on you.

You will gain a solid amount, just off the o.d. change alone, not short and long tubes.

For a longtube comparison, here is my real world situation:

I had a 162k bottomend (1993). This was topped off with AFR 165, OTB Performer Intake, and a custom camshaft, rusted out Mac 1.625" headers (pinched).

I decided to make a few changes, after a couple circumstances. The local track (that I frequent most) is a 1000 ft. track. Best run, off the street was a 10.65 @ 97.98 MPH with the combination above.

Okay, the changes I made were, rebuilding the bottomend (306). I used Probe's 030-10682 pistons (9.6:1 now), with more swept volume that will increase compression. KC did the bottomend.

I also replaced the old rusted short headers, with new BBK Longtubes and a new Offroad H (no dents like my last pipe). I then had Tom Moss port the lower to match the AFR 165cc heads, and he matched them great. Looking down the port, it matched the flange nicely. I even trimmed the gaskets (not done before), cleaned everything as clean as possible as well.

So these three changes were made:

- 306 (slightly more compression)
- Longtubes with H-pipe
- Ported lower to match AFR 165
- RP synthetic tranny fluid

After several runs throughout the next year, the best run I could get was 10.56 @ 99.31 MPH.

I kept the same exact timing, fuel pressure, driver weight, tire pressure, etc. I noticed a little more pull about 5300+ RPM, which I attribute to the lower porting by Tom.

A total gain of 1.33 MPH and .09 seconds. So roughly 13.30 HP.

I feel if you are going to get headers from scratch, go for longtubes, but do not believe the hype on how much better they are.

By the way, the "302 parts make 302 power" is a total fluke. It is based off some truth and some exaggeration.

Just look at Paul's ride. There are literally thousands of cars like his. If you increase the cubes, you increase the power (same top-end).

A 302+ style rotating assembly is lighter than a 351+ rotating assembly. That is more power, cube per cube.

 

[1slow95]

My LT's scrape on EVERYTHING, BUT 1)They're Kooks race headers and hang lower than most brands and 2)My car is ridiculously low. When I had just sportlines it wasn't that bad, it was after I installed the k-member that it got really bad. Right now I would guess the front is dropped close to 3".

I thought about switching to mid lengths, but that's a good bit of work and money for a probable HP decrease. Plus I need to raise my car up anyways, so I'm planning on getting coil-overs instead. Just need some $$$ first.

 

[Pokageek]

"A 302+ style rotating assembly is lighter than a 351+ rotating assembly. That is more power, cube per cube."

Hmm... well my car is a little different in that I have the lightest weight connecting rods Rick had so it prolly is better than average.

Yea I was thinking of your car Mike and Chris's vert, both of you complained of scraping. But you have kooks which in my o are way over-rated, not in power but in quality.. They leak and ride too low. Mine are accufab 1.875" non-crimpled, I do not know if that means spl. I have a dual bolt pattern on my heads. Nice.