offenhauser inake + headman headers
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offenhauser inake + headman headers
i recently bought both of these but now im wondering if its a good idea or not. i noticed that the headers dont bolt to the intake at all. i do alot of 4x4ing and both of these items are fairly heavy, i would hate to have a bolt snap off or something. should i just return these headers and look for a EFI exhaust manifold in the junk yards? will the EFI manifold bolt up perfectly to the offenhauser intake without messing around too much?
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Curious, what do you mean bolt up to?
The exhaust manifolds or headers are seperate from the intake and are held to the cylinder head, by a shared bolt head, odd but true.
Keep the headers.
I would measure the intake and exhaust flanges (thickness), to be sure they are nearly the same.
The exhaust manifolds or headers are seperate from the intake and are held to the cylinder head, by a shared bolt head, odd but true.
Keep the headers.
I would measure the intake and exhaust flanges (thickness), to be sure they are nearly the same.
Last edited by Motorhead351; Dec 12, 2005 at 08:24 AM.
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what i mean by bolt up, is my stock intake and exhaust manifolds bolt together to form one unit that just bolts on to the side of the block. it looks alot more sturdy and solid that way. on the bottom of my offenhauser intake is the same bolt holes and the same square shaped fitting that should technicaly bolt up to my old exhaust manifold, if it didnt shatter into pieces when i was trying to sepperate it from the intake. the headers dont seem to have any way of connecting to the intake, so i was just wondering if this is going to put extra strain on the bolts and possibly even create vacume leaks from moveing around
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From: boondocks, tennessee
if you do decide to look for a stock exhaust manifold let me know. i have one off of a 66 300 that i will give to you for the cost of shipping. i took it off almost a year ago to date when i bought my hedman hedders. its just been laying in the bed of an old chevy in my barn since then
Post Fiend
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From: St George, SC I-95
Psyte,
I just put an intake and efi manifolds on my '79 300 and you need to buy the washers that originally came from an efi (87-up) 300. They are about 1-1/4 in diameter and are about 1/4 to 5/16 thick and have 3/8 bolt hole. I also had to buy a gasket set from a 87-up 300 efi because the efi manifolds were slightly thinner in the flange but hopefully you wont have this problem. The washers cost me about $4 each and I needed 13. I will send you a pic if you need one
I know you are talking about headers but I think since you need the header and the intake to use the same bolt hole its the best way. DO NOT USE PLAIN OL' 3/8 FLAT WASHERS BC THEY WILL WARP AND CAUSE AN EXHAUST LEAK! do it right the first time.
I just put an intake and efi manifolds on my '79 300 and you need to buy the washers that originally came from an efi (87-up) 300. They are about 1-1/4 in diameter and are about 1/4 to 5/16 thick and have 3/8 bolt hole. I also had to buy a gasket set from a 87-up 300 efi because the efi manifolds were slightly thinner in the flange but hopefully you wont have this problem. The washers cost me about $4 each and I needed 13. I will send you a pic if you need one
I know you are talking about headers but I think since you need the header and the intake to use the same bolt hole its the best way. DO NOT USE PLAIN OL' 3/8 FLAT WASHERS BC THEY WILL WARP AND CAUSE AN EXHAUST LEAK! do it right the first time.
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ill deffinately be getting new high strength bolts/washers. is there any way i can stop the bolts from backing out? im guessing i cant use lock washers, and threadlock burns out when exposed to heat. i found myself tightening the bolts for the intake/exhaust almost every couple of months because they were constantly getting loose.
Post Fiend
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From: St George, SC I-95
Psyte,
I used grade 8 bolts and the washers I mentioned. I would not use anything else. I think they make high temp lock tight if you want to use that.
I used grade 8 bolts and the washers I mentioned. I would not use anything else. I think they make high temp lock tight if you want to use that.
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From: Jackson, Tn
STG, if I read your post correctly, you replaced the bolts/studs that hold the assembly to the head? I'm trying to find what size and thread pitch bolts or studs to get since I don't have a lot of downtime when I start work on my truck to replace some gaskets. I'm trying to ensure that I have everything I need at hand when I start. I've already got one I'm going to have to drill out and I want to be ready in case I have to do more.
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Post Fiend
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From: St George, SC I-95
A-
Im 99% sure that the bolts were 3/8 x 1 1/2 grade 8 coarse thread and the washers were from Ford. I bought an intake/exhaust gasket set for 79 300 and also an intake/exhaust gasket set for a 87 300. Here goes the explanation! The correct 79 gasket set is a one piece deal and my intake flanges and efi exhaust manifolds were slightly uneven, maybe by a couple thousandths (sp), so I used the exhaust part of the two piece 87 gasket set to raise my manifolds to the same height as the intake. Then with alot of help from my buddy we got the bolts started and tightened down. It really does help to have 2 people when installing the manifolds and intake because if they are not perfect the washers will not tighten down enough and you will have an exhaust leak. If I can help or if you need pics please let me know....that goes for anyone
Im 99% sure that the bolts were 3/8 x 1 1/2 grade 8 coarse thread and the washers were from Ford. I bought an intake/exhaust gasket set for 79 300 and also an intake/exhaust gasket set for a 87 300. Here goes the explanation! The correct 79 gasket set is a one piece deal and my intake flanges and efi exhaust manifolds were slightly uneven, maybe by a couple thousandths (sp), so I used the exhaust part of the two piece 87 gasket set to raise my manifolds to the same height as the intake. Then with alot of help from my buddy we got the bolts started and tightened down. It really does help to have 2 people when installing the manifolds and intake because if they are not perfect the washers will not tighten down enough and you will have an exhaust leak. If I can help or if you need pics please let me know....that goes for anyone
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From: Federal Way, WA.
Psyte, what is this going in, f-150, 250, bronco? i am in the market for a header and i looked at the headmans, and they dont say anything about working with a bronco, which is what i have.
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its an 85 F-250 4x4. i couldnt find a set of thick washers anywhere so i decided to make my own out of 1 inch round bar 1/4 thick. i also bought some grade 8 bolts to go with it. the only problem is i dont have that tiny spacer that goes between the washer and the bolt head. ill be installing all of this stuff probly on saturday so i can actualy have some daylight (i work during the day and it gets dark around 5pm.) looks like it might be a tight fit for the headers though.
Fleet Owner
Joined: Sep 2005
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From: Lake Tahoe, Nevada
A neat trick is to replace manifold bolts with stainless steel studs. Use the thick washers, and thick brass or bronze nuts. When you install the studs, (using two nuts locked together,) apply loctite. In the head, the loctite will last. The nice thing is that this combination won't rust up nor will the threads gall.
If the intake and exhaust flanges don't match, (measure them with a caliper beforehand,) then you can grind (or mill,) one side of the washer down to compensate.
If you are a machinist like Psyte, you can make your own washers out of stainless and polish them up while they are still in the lathe.
If the intake and exhaust flanges don't match, (measure them with a caliper beforehand,) then you can grind (or mill,) one side of the washer down to compensate.
If you are a machinist like Psyte, you can make your own washers out of stainless and polish them up while they are still in the lathe.
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alright.... i got some big problems now. everything is installed(some of those header bolts were extreamly hard to get in) but now none of my old hoses and throttle cable will hook up to the carb. as far as i can tell theres only 2 vacuum ports. the big one one is for either the brake booster or PCV and the other small one is im guessing for the vacuum advance on the distributor. can anyone tell me wich way this carb is suppost to face? also, what should i do about the throttle cable situation? do i have to get a new one? or is there a bracket i can buy?
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someone should really make an article with step by step procedures and a full list of parts required for this application. some things i didnt know i needed were; a carb spacer(the throttle linkage hits the runner on the intake), a custom throttle bracket (no one sells anything even remotely close), a vacuume fitting for the pcv/brake booster and a block off fitting for the other hole on the intake manifold, 4 carb studs (neither the intake or carb came with any), a new hose for the brake booster/pcv so it will actualy reach around to the passanger side (unless yours was long enough). really though, when headman made these headers, were they even considering how to get the bolts on? the bolt under the first runner at the front was going down right infront of the bolt, there was literaly an inch of clearance and the only way i could do it was with a stubby gear wrench with only enough room for a quarter turn.