Exhaust manifold to aluminum head

[johnbeck]

A friend said to use anti seize on the exhaust manifold bolts going into my aluminum heads. He said it prevents galling. Anyone experience difficulty removing manifold bolts from an aluminum head after years of use? What should I apply to the threads? Thanks

 

[BUCKWILD]

yes anti size, any steel bolt in aluminum will gall including the spark plugs

 

[johnbeck]

Which direction does the exhaust manifold gasket go, aluminized metal toward the aluminum head or toward the cast iron manifold? Thanks

 

[blubuckaroo]

Why would anyone waste money on aftermarket aluminum heads, and be restricted with iron manifolds?
Even the best, matched and polished, manifolds are going to be the restriction here.
If you just want "the look," use spray painted E7 iron heads.?:?

 

[Broncobowsher]

I'm guilty of ported K-code manifolds on Trick flow heads. Ran just as good as a set of headers. So go for it.

Having worked with factory combos, use some anti sieze if you ever want to remove them after 100k miles.

I believe Frieburger's comment building the covid 350, when in doubt, foil out.

 

[johnbeck]

The cast Irons are my original manifolds. I'm installing them just for twenty minutes of breaking in the engine. I bought 289 H.P. K manifolds and tried to make them fit. The passenger side was great. The driver side hit the motor mount tower. It would require half a day plus to scalp off three quarters of an inch so the manifold would clear. I'd rather the low maintenance manifold above header headaches for the miniscule gain of four to five per cent h.p. and torque.That together with the header heat nightmare. People on this site that I respect their opinion have suggested mid length Hooker Headers as a compromise for my wants - probably what I'll end up with. Thank you all for taking the time to respond. John B

 

[chuck1022]

Why would anyone waste money on aftermarket aluminum heads, and be restricted with iron manifolds?
Even the best, matched and polished, manifolds are going to be the restriction here.
If you just want "the look," use spray painted E7 iron heads.?:?

Go to YouTube and watch the engine masters where they test exhaust manifolds..shorty and long tube headers.

My takeaway...short tube headers are a waste...long tube are good for upper rpm power gains (exactly where I don't operate my bronco). Factory exhaust manifolds are surprisingly good.

 

[bronconut73]

Long tube headers build low rpm torque though increased scavenging.

 

[chuck1022]

Long tube headers build low rpm torque though increased scavenging.

I will take your word for it... I know wherever I watch all the engine build shows...the dynos test from 3500-7500 rpm.

I would like to see 1000-3500 power numbers.

 

[blubuckaroo]

I will take your word for it... I know wherever I watch all the engine build shows...the dynos test from 3500-7500 rpm.

I would like to see 1000-3500 power numbers.

I agree.
The most restrictive part of a small block Ford motor is the exhaust. That's because of the angle the runner leaves the chamber. That's also where the Boss/Cleveland head has an advantage.
To help with this restriction, the scavenging of a set of long tube headers will really wake up a small block Ford in mid range torque, no matter what you read about high RPM horsepower numbers.

 

[Broncobowsher]

I will take your word for it... I know wherever I watch all the engine build shows...the dynos test from 3500-7500 rpm.

I would like to see 1000-3500 power numbers.

The typical water brake dyno can't load one down that low. They can make them load that low, but they can't take the RPM on the upper end. And if you are buying a dyno for a performance shop you buy a dyno that has the RPM band of where you will be doing your testing at.

I did a chassis dyno and locked the torque convertor just off idle, that got me numbers starting at about 1200. There is no HP down there, only a torque number. And it isn't that impressive compared to higher in the RPM band.

 

[chuck1022]

The typical water brake dyno can't load one down that low. They can make them load that low, but they can't take the RPM on the upper end. And if you are buying a dyno for a performance shop you buy a dyno that has the RPM band of where you will be doing your testing at.

I did a chassis dyno and locked the torque convertor just off idle, that got me numbers starting at about 1200. There is no HP down there, only a torque number. And it isn't that impressive compared to higher in the RPM band.

I love watching all of Richard Holdener's videos...but it is mostly high rpm stuff. My 302 seldom...if ever revs above 4000rpm.

 

[Quick & Dirty]

Speaking of Holdener, here is a screenshot of stock 5.0HO dyno curves with shorties and 1-3/4" Hooker Fox-chassis long tubes. The biggest improvement is in the 3000-4000 rpm range.

Edit: I'll put up the one with the GT40 intake added.

 

[Broncobowsher]

The cast Irons are my original manifolds. I'm installing them just for twenty minutes of breaking in the engine. I bought 289 H.P. K manifolds and tried to make them fit. The passenger side was great. The driver side hit the motor mount tower. It would require half a day plus to scalp off three quarters of an inch so the manifold would clear. I'd rather the low maintenance manifold above header headaches for the miniscule gain of four to five per cent h.p. and torque.That together with the header heat nightmare. People on this site that I respect their opinion have suggested mid length Hooker Headers as a compromise for my wants - probably what I'll end up with. Thank you all for taking the time to respond. John B

In that case the direction of the gasket doesn't matter. Anti seize is still fine to protect the threads. For the couple of heat cycles you will see a couple drops of motor oil will even work fine. Just don't use any stainless fasteners, they don't play well with aluminum.

 

[johnbeck]

The stainless aren't good on aluminum, how about grade 8 bolts? Should I use a lesser grade? I bought #8 3/8th bolts today from specialty Tool. The threads look like they have less material than most bolts. I really don't want to "tap" different pitch or depth threads in the aluminum.