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Hi guys,

I'm trying to decide on headers for my 347. I've got my choice narrowed down to Accufab and FPA, as they both make a nice early Mustang 1 3/4" header with a wide bolt pattern flange (which I'll need with the planned heads).

The Accufabs primaries seem quite a bit longer then on the FPA's, how will this affect performance?

http://www.fordpowertrain.com/347step.htm
Vs.
http://www.fordmuscle.com/forums/all-ford-techboard/accufab-headers-and-prothane-mounts_51772.html

I already heard Thordane65's praise for the Accufab's but does anyone else have expierence with either of these headers before I make a decision?

TIA
 

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I have a set of FPA headers for my cleveland in a 1970 mach 1, they fit excellent, no part of the header is below the oil pan and they come on and off without having to pull or tilt the motor. Clears the clutch linkage well and the ball flange collectors are very nice since there is good movement to get the rest of the exhaust seated where I want it. Longer tube will increase bottom end torque, shorter tube with increase top end power. I am very pleased with these headers.
 

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Thordane's 1 3/4" headers didn't really fit in his 65-66 engine compartement with the 302. He posted about it some time back. He choose to replace a section of tube to make them fit. Guess you could also "massage" the shock tower. I seem to recall he wasn't very happy about that.

I've seen a pair of the Accufabs in a 65-66 engine bay with a 331. One of the tubes had to be dented pretty darn good to clear. Just thought you should know.

Oops! Just saw that you already posted the link to Thordane's thread.

<font size=-1>[ This Message was edited by: 289nate on 10/13/06 4:26am ]</font>
 

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I am using prothane mounts which are different than the stock mounts. I talked to george klass of Accufab and he said that with the stock mounts, they will fit perfectly.
Dennis111 also uses accufabs... and I think stock mounts. He may be able to shed some light.
Theres no question that with the prothane mounts, you'll have to "massage" that rear tube!
 

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I don't know what mounts the 'stang I've seen had. He did have to really smash that tube to get it to fit. It'd be great if you're right.

Dennis also has a 351 block instead of a 289-302 block. Not really the same.
 

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On 2006-10-12 15:41, 289nate wrote:
I don't know what mounts the 'stang I've seen had. He did have to really smash that tube to get it to fit. It'd be great if you're right.

Dennis also has a 351 block instead of a 289-302 block. Not really the same.
True, I have a 351w block which is wider and taller than a 289/302 plus I use the early 65' motor mounts which drop the block about 1" lower than the late 65-70 mounts. I also have high port heads. I did a little minor relieving of the shock tower to ensure tube clearance. I had NO problems with the rear most tubes--including clearing the stock4 speed Z-bar. Pretty sure that if I would have used the late 65-70 motor mounts, I wouldn't have had to do the shock tower mod. Overall, I am very happy with my Accufabs.

Personally, I would think that it wouldn't be that hard for either manufacturer to make a decent fitting header for the narrower 289/302 block and stock motor mounts.



_________________
Dennis

65' STANG, 3160 lbs

393W NA, 2.78 Toploader 4 Spd, 9" 3:70 Posi
Pro Comp Heads, Vic Jr. Intake, 750dp, 236/561 Solid Cam, 9.6CR, 1 3/4" Headers, Lakewood, Subframes, Caltracs



<font size=-1>[ This Message was edited by: dennis111 on 10/13/06 7:32am ]</font>
 

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FPA all the way. Check some posts regarding headers.

FPAs outpowered two other header brands on the dyno.

And they fit like a glove!
 

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Longer primary tubes provide more low end performance. bigger and shorter primaries need flow to make them work and that happens with RPM and lots of it. You can also gain some low end with your collectors. You can tune the length (the diameter should be the same as the header outlet) with either a stop watch or by the sound (if you have a good ear). Typically the collector should be between 10 and 18 inches long. If you are going to run an "H" pipe you should stick it in those collectors. Then you can weld flanges on the collectors and run your street pipes from there.
Paul
 

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The FPA's will fit YOUR car. Stan takes pride in making sure they go on and off smoothly. I bought the stepped headers and am very happy.
 

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I have accufab 1 3/4 headers in my 65 mustang with a 331. I have solid mounts now but had the motor sitting in the car on prothane mounts.On the passanger side #1 tube goes down and then back along the block and mount....no way were they going to work with the big multi piece prothane mount. Stock mounts may work ...but I didnt have them. I made solids with a cut out for the tube to sit in. Nice headers and they work well with my set up.....Ive run 10.66 @ 125.6 on motor so far just be aware of the motor mount issue. Hope this helps if ya have more questions just ask!
 
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