400 sbc build

[sacked-HQ-wagon]

Have just purchased a 400 chev but have heard that they have some overheating problems. Looking at upgrading the heads, possibly to alloy, and was wondering what my options are? An article i was reading said something about the heads needing steam holes?

[coopers308]

Because the 400 chev has siamesed bores it has steam holes either side of where the bores meet to stop hot spots and keep the flow going in these dead areas. If you are fitting any aftermarket heads on these blocks they have to have the steam holes drilled in the heads otherwise you are blocking them off at the block and that will cause hot spots. Easy job though just use the 400 head gasket as a template and drill them. I think there is 6 per head.

[bad Q]

i have a 400 chev with ally rhs heads,no over heating

[sacked-HQ-wagon]

do the alloy rhs heads have steam holes already in them? do any aftermarket heads have them pre drilled for 400cid? was thinking about a set ofProcomp Pro Series 195cc 2.02/1.60 BARE aluminum cylinder heads?

[bad Q]

sorry bloke i couldnt tell ya,a mate built the motor,all i no is it doesnt over heat,as ive heard about 400s overheating too

[bad Q]

u arent lookin at pro comp r u

[TRIKHQ]

Don't go near them, do your research and you will see they are trouble.

If you were closer a mate here has a set of AFR's 180cc for sale, complete $1500.

You will have to drill steam holes in whatever you get I think, have not seen any heads predrilled.

[sacked-HQ-wagon]

Procomp = bad?

What would everyone recommend? What size chamber heads should i be using?

[55DART406]

I ran a 400 GM block for a little while ,never overheated with a HG v8 radiator and my new block never gets hot either with ally heads. Just make sure the block is checked out really well before you spend money on it. The original blocks had quite a few problems. I wished I had just gone straight to the Dart block in the first place.!!

[55DART406]

What are your specs . ? Cam, compression, manifold,carby,etc.etc. How fast do you wanna go?

[sacked-HQ-wagon]

2 bolt block, has just been bored to 30thou over. Unsure of cam or compression. Want it to run on 91 or 98 unleaded. Looking at about high 300 to 400 hp. Thinking of buying all new top end.

[bango]

If looking for new topend,how about a pair of SB2.2 Heads....these heads are used in NAScars.....

[paulzig]

SB2.2's arent that cheap , if you buy them on ebay there might be a lot of money fixing them up if they arent right

[Luke in SA]

Hmmm... A Nascar engine isn't quite the type of engine you would run in a street car.

Not exactly sure of port volume with the SB2.2 head, but it may be a bit large for your street bruiser.

If your on a budget and want some quality heads, then a nice pair of Iron Sportsman II's will wake up your Chev.
Alloy heads aren't too badly priced at the moment also.
AFR, Dart are up there with the best of them.

[gas 84k]

If your on a budjet vortechs are a good choice will make 450+ hp and 500ft\lb with a cam around 230@50 rpm air gap and 750 pumper all under 5500 will be a real stump puller.
A sb.2 will not work on a street combo lol.