Headers vs. Stock manifolds & elec. Fan

I've put a 429 in my 1970 mustang and I have a set of headers from crites restoration that I bought used. I was wondering how much horse power difference there would be between the headers and the stock manifolds? I am leaning towards using the stock manifolds. The headers are a nightmare to get in and once their in they prevent being able to work on the steering arms, due to them going underneath everything. Also, I am planning on putting on an electric fan, is there a particular model or brand that someone would recommend? Should it be a pusher or puller. I do have an AC condensor so I was thinking a puller? Thanks for the help.

well if your going to race the car and want all you can get out of the engine headers are the way to go ,if not the convenience of the stock manifolds is nice. you can always do a little work to the stock maniflods to open them up a bit and smooth them.
ive even seen a process called extrusion where they squeeze a abrasive putty through the manifolds to hog them out dont have a clue who does it.

if it was me and i had a 70 mustang with a 429 i would have a mechanical clutch style fan on it as it will do a good job and especially if the engine is warmed up a bit so it runs hot.
other than that the biggest electric you can get behind the rad cause i think shes gonna heat.
good luck

If you are going electric fan, go puller (behind rad) if you have room, with a shroud. General opinion is that Spal seems to move most air, from previous posts on this subject.

Those big block Fords tend to fill up an engine compartment, don't they? Sure are great engines, though.


Don

Where would be a good place to take the exhaust manifolds to have them smoothed out on the inside? Or should I just use a drimil tool myself? Thanks for the info on the elec. fan. I want to go with an electric to save a few HP, since I'm not using the headers. I'm not racing the car, but I would like it to be as strong a runner as I can on a teachers budget. : ) Thanks for the good ideas!

Kevin

"I want to go with an electric to save a few HP"

In my opinion, there are better ways to make a few more HP. I also think you're gonna have a problem cooling it with an electric fan, but I could be wrong.

If you can't be talked out of an electric, at least use the daddy of them all, the Lincoln Mark VIII.....
http://lxsteed.stangnet.com/photo4.html
http://www.geocities.com/smithmonte/...rkVIII_Fan.htm
http://members.tccoa.com/392bird/markviii.htm
http://www.dccontrol.com/

Another reason for the elec. is that I'm not sure I can fit a fan clutch and fan in the space. My radiator is still getting re-cored so I haven't got an accurate measurement yet, but I'll check it carfully when I get it back. It would be simpler to run a regular fan. How much HP do you think you can save by going to an electric? Thanks for your help.

Kevin

make shure the manifolds are port matched so that there are no bad edges for the exhaust to hang up on them and then start from there smooth anything that can be smoothed. one problably wont gain too much but i have seen some manifolds with big ugly casting blobs sitting inside of them and that cant be good for anything

use a high speed dremel with the flex extender and a wire wheel and run it through as much as you can til its as smooth in there as you can possibly get it....you wont gain much but you will gain a little.... another option would be to purchase shorty headers, they're less in the way but they're still very much a pain to install on that car.... you will have a little more difficulty accessing the spark plugs, which i'm sure you already have some difficulty atm..... probably not as bad as my brothers maverick with the 390 in it tho :CRY:

As soon as I get my manifolds back from getting the cracks welded I'll give the dremel idea a go. I saw a 1970 mustang on ebay that had the shock towers removed to allow all sorts of room in the engine bay. They had some kind of short springs and short shocks that did not need to stick up into the tower. I was wondering if that was some sort of conversion kit or a custom job. It sure would make this motor swap a lot easier. Thanks again

Kevin

Yup, there are IFS packages available to fit the Mustangs. They free up a ton of room in the engine compartment and help the handling and braking, too.

What does IFS stand for, and where can you get them, and about how much do they cost? Thanks a bunch!!!

Kevin

Ifs is like mustang II style. I have a 460 in a falcon and installed Sanderson shortys although had to move the flange back one hole and retube on side. My engine suffers with these. A real header will really help torque and upper rpm power. I use a stainless flex fan on the waterpump, a cicular metal shroud ala streetrod and a elec pusher on front. Ran hot with other combos. I have a temp switch on the front elec. Radiator is a custom vette crossflow with ford tanks 3 row. Still overheated till above combo. Without welding shop tools ,an ifs will be $3000 easy for someone to put one in. I bought my crossmember from rod&custom motorsports. Used old ford and chevy stuff to put it all together, ex granada rotors and monte carlo calipers.

the IFS packages are great i'd love to get one for my mustang if i could afford it....

BTW i dont know about using the dremel method on cast iron manifolds if they've cracked and been repaired.... cast iron manifolds tend to break once they've been repaired anyways.....