CHEVY Summit heads

[1320John$$$]

Anyone ever use the summit stock replacement cylinder heads non Vortec looking for a cast iron head for my 400 small block nothing fancy motors going in a daily driver comp 268 camshaft

 

[Wageslave]

While I have heard mostly good about their heads, I would be concerned about this particular choice because of the 72cc chambers. Unless you are running dome or at least flat top pistons, your compression could be pretty low with the large chambers (think 7:1 to 8:1 with factory dish pistons).

I realize that power isn't a primary concern, but if the money is going to be spent anyways, 64cc or maybe even 57cc heads are going to up your compression and make the motor more efficient for the same money spent.

Also whatever you buy, don't forget to drill the steam holes.

 

[1320John$$$]

While I have heard mostly good about their heads, I would be concerned about this particular choice because of the 72cc chambers. Unless you are running dome or at least flat top pistons, your compression could be pretty low with the large chambers (think 7:1 to 8:1 with factory dish pistons).

I realize that power isn't a primary concern, but if the money is going to be spent anyways, 64cc or maybe even 57cc heads are going to up your compression and make the motor more efficient for the same money spent.

Also whatever you buy, don't forget to drill the steam holes.

-12.5cc volume
.020 in the hole
Fel pro gasket
72cc chambers in the head more like 9.4 compression
So I won’t need a lot of gear with these heads in my 72 Chevy pick up

 

[1320John$$$]

So when I drill the holes in the new heads are the ones towards the intake face on an angle or the ones on the exhaust face on an angle
My Brodix heads came with holes drilled straight in unlike the factory ones

 

[Wageslave]

So when I drill the holes in the new heads are the ones towards the intake face on an angle or the ones on the exhaust face on an angle
My Brodix heads came with holes drilled straight in unlike the factory ones

You would have to contact Summit and ask what is appropriate for that head casting. Once you get away from a factory GM casting, you just don't know where the cooling channels are.

 

[Old ElCo Dude]

I have a 406 in my 71 and I used World products Sportsman II 220's.I drilled them at home with a drill press using the factory angles but I agree the steam holes have to meet the coolant passages correctly.I will try to find the angles for you and post them, but when you look at the 400 head gaskets against the head you can see how the steam holes go.IIRC you drill the exhaust side of the head straight down this matches a hole on the blocks deck and the hole on the intake side is drilled on an angle but this hole also lines up with a hole in the deck.
OK I found some info that tells how to drill steam holes :

Drilling steam holes in smallblock Chevy heads

www.crankshaftcoalition.com

There is more information about drilling steam holes on the Team Chevelle web site.Do a search on the forums on Team Chevelle.......www.chevelles.com ...... you will find a lot of Chevy information on there and its free to sign up, that way you don't get bombarded with commercials
The other thing about drilling those heads is to get in touch with the manufacturer of those heads and let them know they're going on a 400 SBC.You're gonna love the low end torque that motor puts out but if it's going in a street motor it will run HOT without the steam holes.

 

[1320John$$$]

I’m just going to drill them like I’ve always have on an angle like the stock ones are drilled
I still haven’t decided on what heads I’m going to purchase
Looking at others like
EQ IMCA
Dart Iron Eagle SS
The Chinese Promaxx
Dart Iron Eagle 180cc if I plan on spending the money

 

[1320John$$$]

I have a 406 in my 71 and I used World products Sportsman II 220's.I drilled them at home with a drill press using the factory angles but I agree the steam holes have to meet the coolant passages correctly.I will try to find the angles for you and post them, but when you look at the 400 head gaskets against the head you can see how the steam holes go.IIRC you drill the exhaust side of the head straight down this matches a hole on the blocks deck and the hole on the intake side is drilled on an angle but this hole also lines up with a hole in the deck.
OK I found some info that tells how to drill steam holes :

Drilling steam holes in smallblock Chevy heads

www.crankshaftcoalition.com

There is more information about drilling steam holes on the Team Chevelle web site.Do a search on the forums on Team Chevelle.......www.chevelles.com ...... you will find a lot of Chevy information on there and its free to sign up, that way you don't get bombarded with commercials
The other thing about drilling those heads is to get in touch with the manufacturer of those heads and let them know they're going on a 400 SBC.You're gonna love the low end torque that motor puts out but if it's going in a street motor it will run HOT without the steam holes.

I plan on using my Bridgeport mill so I have a better chance of the angle being spot on
Back in the late 80s we use a hand drill to put the holes in the camelback heads that seem to work pretty good on them 400s we never had any overheating problems with them

 

[1320John$$$]

You would have to contact Summit and ask what is appropriate for that head casting. Once you get away from a factory GM casting, you just don't know where the cooling channels are.

We are getting off topic here I wanna know about the cylinder heads not drilling the steam holes that’s 80s news

 

[1320John$$$]

So my EBay/Amazon heads will be here Saturday not expecting much going to use PAC springs comp hardware not sure on the valves I see people running them but never on anything that is WOW fast
I plan on picking them apart and taking lots of pictures
The valve seats and guide angle are going to be my main focus