Ford Muscle Cars Tech Forum banner

1 - 8 of 8 Posts

·
Subscriber
Joined
·
43 Posts
Discussion Starter · #1 ·
To make it short, I'm trying to bolt my idler arm pulley bracket from March to my AFR 165 heads. The two holes on the left hand side of the March bracket are drilled for 3/8's inch bolts, but the holes in the heads are 7/16's inch. My options, that I have been able to come up with, are:

1) Drill 1/16 out of the March bracket hole and use a 7/16th in. bolt instead of the 3/8's, an idea March really didn't like

2) Drill out the treads on the AFR heads, retap the hole and use a heli-coil insert to use the 3/8's in bolt.

By the way, I think I'd much rather do 1), but does anyone see any glaring problems with drilling out 1/16th of a hole in a March bracket? I can't forsee any alignment problems because of it. Any other solutions I don't know about?
 

·
Premium Member
Joined
·
827 Posts
Ran into the same problem bolting the power steering onto my 69 mustang with Trick Flow heads. There are threaded inserts that go in to those holes and they have an internal thread as well to reduce the bolt size. Not sure of the number right off hand but they are available. I'll try to get the number or maybe someone can chime in with the part number. I know Ford sold them for a while....hope this helps........John
 

·
Registered
Joined
·
176 Posts
well i just got them for my world products heads the hole is big because to make it emissions legal it has the have the crossover pipe in the back of the head for the airpump and its on both ends becasue they can be installed either way the ones in my heads were 9/16 and ford sells a insert to put in there and there not cheap retail is 20$ each so if that is what you need ford has them but you might try an auto parts stor instead and see if they can get them

jeff
 

·
Registered
Joined
·
4,520 Posts
Most companies (or vendors that sell sbf heads) are keenly aware of the needed reducer. I am surpised they did not come with the head.

...ALTERNATOR BRACKET:
Some years require the supplied 5/8-11-7/16-14 reducer to be installed into air pump thread in order to properly mount the alternator...
http://www.airflowresearch.com/sbf_install.php

maybe things have changed?

A few years back...I was able to pick them up at the local Ford parts shop. I don't know if there is an official P/N, there should be - but I've never heard of it. If the parts guy is a FMS fan, he should be able to find them without any trouble.

FYI - they have a listing for head bolt/studs bushing reducer for useing 7/16 drilled block fasteners to hold heads drilled for 1/2 bolts

...HEAD BOLTS or STUDS:
High quality head studs or head bolts with hardened washers must be used to prevent galling of the aluminum head. Recommended head bolts are ARP #154-3701 for engines with 7/16" head bolt holes (289 and 302 CI). Engines with 1/2" head bolts holes (351-w and 302 CI SVO) should use ARP # 154-3603. For maximum head gasket-clamping AFR recommends head stud kits. AFR part #1420, #1422, #1450, #1451, and #1492 heads come with head bolt hole drilled to 1/2". If installing on a 289-302 block with 7/16 threads, a head bolt reducer bushing 1/2 to 7/16 must be used, AFR part #6324. ...
Ford motorsports (ARP) also sells "neck down" bolts that do the same thing, they are 1/2 bolts which have been reduced to allow them to fit the stock 5.0 litre deck drilled for 7/16 head bolts.


<font size=-1>[ This Message was edited by: Beoweolf on 9/20/06 7:32am ]</font>
 

·
Subscriber
Joined
·
43 Posts
Discussion Starter · #5 ·
Thanks for the replies... yeah, I know the air pump holes that y'all are talking about, and I've already plugged those up (I believe the bushing for that was called a Thermocator pump bushing, from what I was told).

However, the two holes I am talking about at this time are the other two holes on the head, closer to the center of the engine. One is more towards the top of the head, the other more towards the bottom. At my local performance shop, they said that on every head they've ever dealt with, regardless of brand, these two holes were 3/8th's inch. However, on these AFR heads, the holes are tapped to allow a 7/16th bolt at this time. I need it to be reduced to 3/8th's inch on the inside diameter, so I don't think that the thermocater bushings will work, because I think they're too big already. So, I need the reducer's outside diameter threads to fit a 7/16th, and the inside diameter's threads to fit a 3/8th. Please forgive me if you've already answered this and if I'm just confused. But please tell me if I am. Thanks!
 

·
Registered
Joined
·
176 Posts
no i think your probabaly right it should be 3/8 you might have to find something like a heli coil to put in there to reduce or drill all your brackets which would not be a good option

jeff
 

·
Registered
Joined
·
1,904 Posts
I'd just drill out the brackets to 7/16 and call it good. The 1/16 oversized hole in a pulley bracket shouldn't hurt a thing.
 

·
Registered
Joined
·
1,604 Posts
I had the same problem with my AFRs. I cut off a grade 2 bolt and screwed it into the head, then drilled and tapped for the right size bolt. As mentioned above, it probably won't hurt just to open up the bracket hole.
 
1 - 8 of 8 Posts
Top