just finished rebuilding my 425

[coast]

[coast]

Thanks to Russell Martin for all of his valuable information

[Guest Rob J]

Looks sweet, what are you dropping it in?

[Guest Rivit]

Looks terrific mate.. You can drop it in my thing if you want...hahaha Only playin.. :cool:

[coast]

Hey Rob,

I put it in a 65 Riv GS. Really strong motor, only problem is my trans went out. Having it rebuilt, should be good to go after that.

Bob

[RockinRiviDad]

Wow! Headers! Don't know if I've seen headers on a nailhead. Visually pleasing…good job…more pix

Regards,

David

[coast]

I was kind of concerned about going with the headers due to heat. I was pleasantly surprised to find out they dont put out much heat at all, and cool down fairly quickly. Got they from TA performance, they fit very well and they come out about the same place as the exhaust manifold, so easy hooking up to existing tailpipes. Also, I got them uncoated, I spayed with High Heat paint, both primer and top coat, baked them in my oven to cure per the instructions and so far the paint has held up very well. Will have to give it more time to evaluate but so far so good. One last thing I did was put in a TA 25 cam from TA performance. It I had to do over I might go with the TA 20 due to the idle. But still not to bad.

[RockinRiviDad]

I wanted headers too & a friend of mine building the same car barked "headers on nailheads are useless, the exhaust ports are too small" I didn't know any better…I left it at that…saved me money by not buying them too. But now that I see them…oh man!

Maybe someone will chime in & school me up. If not I might start a thread on the subject if I don't find anything with the search option

Regards,

David

[coast]

its hard for me to tell how much the headers helped as I had lost some much compression before the rebuild I dont know what all is contributing to the new power, just know I gained a lot. The TA performance website claims an improvement in horsepower, I think it was 20 or 30. I have heard the same thing before about not gaining much on a nailhead from headers though.

I tried to post more pics but they all seem to be to big and the site rejects them.

[RivNut]

On the V8Buick.com site there's a forum specifically dedicated to just "Da' Nailhead" engine. Most of the guys over there are running stock manifolds that have been port matched to the heads and then ported out some more, especially as the end where they bolt to the exhaust pipe.

The stock manifolds flow as well as the exhaust ports allow. The guys also run stock manifolds because of they help dissipate heat from the block - no gasket, just like it was assembled at the factory. Their engines run cooler with manifolds as opposed to headers which require gaskets.

Ed

[RockinRiviDad]

I tried to post more pics but they all seem to be to big and the site rejects them.

I know all too well the pain your feeling with the pic situation. I am in the learning process with that too. A member here (Rob J) suggested using a online photo service. Like him I used photobucket. Seems to work well but some pix are loading smaller than the rest. We like pix so Good luck

Ed, thx for the details on the exhaust

Regards,

David

Edited December 19, 2013 by RockinRiviDad (see edit history)

[TexasJohn55]

The stock manifolds flow as well as the exhaust ports allow. The guys also run stock manifolds because of they help dissipate heat from the block - no gasket, just like it was assembled at the factory. Their engines run cooler with manifolds as opposed to headers which require gaskets.

Ed

Ed, could you elaborate on that theory? Once the exhaust is out of the head, it is gone. It would seem that the manifold heat is transferred to the head and then soaked up by the cooling system. If gasketed, it cannot transfer as much heat to the head. How can the hot manifold transfer heat from the engine rather than to the engine, the exhaust gases are much hotter. ????? Help me out here, I don't understand the concept.

I do understand that headers radiate more heat to the surrounding area.

I don't want to hijack the thread, just curious................John

Edited December 19, 2013 by TexasJohn55 (see edit history)

[TexasJohn55]

I tried to post more pics but they all seem to be to big and the site rejects them.

Down load a photo resizer, free from many sites, I use FastStone. That allows my 1 or 2 meg pictures to be sized however I want, I usually size down to appx 50-100 kb which gives alot faster upload times because I am on dialup. If someone emails me a picture without downsizing, it takes 20-30 minutes for each picture. Digital cameras are packing more and more MB into pictures now than used to. You can click on properties and see how many MB your pics are before you upload and resize accordingly. A 50 KB picture looks fine but doesn't blow up and show as much fine detail. Think about how much storage space it saves on your pc and the forum's site as well.

Edited December 19, 2013 by TexasJohn55 (see edit history)

[RivNut]

Ed, could you elaborate on that theory? Once the exhaust is out of the head, it is gone. It would seem that the manifold heat is transferred to the head and then soaked up by the cooling system. If gasketed, it cannot transfer as much heat to the head. How can the hot manifold transfer heat from the engine rather than to the engine, the exhaust gases are much hotter. ????? Help me out here, I don't understand the concept.

I do understand that headers radiate more heat to the surrounding area.

I don't want to hijack the thread, just curious................John

I don't know the particulars but from what I remember it was said that the gaskets tend to hold the heat in the head because the heat has nothing to transfer to (other than the coolant.) The idea was that as the exhaust gasses leave the manifold for the cooler pipes, the heat is transferred from the head to the manifold to the cooler pipes. That's what I remember being said. I can't find who said it or when it was stated. Fact or theory, I don't know; just passing along something I read. Conversely, if there is no gasket between the exhaust manifold and the head, theoretically the heat from the manifold could transfer to the head and take advantage of the cooling effect of the water.

All I know for sure is that the General didn't install exhaust manifold gaskets from the factory; for what ever reason. Unless the head and manifold are machined flat, you will have exhaust leaks. Better to have the surfaces machined. However I could see using them with headers where there is no surface to be machined. .

Ed

Edited December 19, 2013 by RivNut (see edit history)

[alini]

The heads on a nailhead are probably one of the worse designs for exhaust flow but the best for intake. When looking down the port of an intake in the head you can clearly see the back of the valve, so the air flows right into the cylinder. the exhaust on the other hand, the air has to bend over 90 degrees to enter the exhaust manifold. If you dont improve that airflow, headers really aren't going to get you much. You will get some just from the improved flow down stream but the head is still the stumbling block on a nailhead. Kinda why we dont have 'nailhead designs' anymore.

If you read up on the engine you will find that the engine actually flows better backwards when under forced induction. The air forced in the exhaust port doesnt matter about as much flow because its volume is so much increased. The exhaust straight out flow then allows for greater exhaust air escaping.

[RivNut]

Here's a picture of a backwards breathing nailhead in case some one can't picture it in their mind.

[RockinRiviDad]

Crazy!!! I've never heard of such a thing. That "blows" me away lol

Regards,

David