I have just slapped that cam in and used stock heads with no work to heads but it a chance i was taken. The machine shop is correct. Most stock heads are limited to around 480 lift you may get awAy without it but not worth the risk. All that is really needed is the valve guides to be cut down and maybe springpocket opened up depending on diameter of springs. If That kit comes with springs so you are good there. I have used that same cam in many motors you will be very happy with it. Has good street manners along with the power. I had a 355 sbc 9.7:1 with stock heads going 12.43 and still got 15mpg car has th350 and 373 gears. The machine work required shouldnt cost much at all if you are getting heads redone.87ttop said:
400 sbc build
- Thread starter 87ttop
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it comes with springs, and everything but I was wondering if a stock set of redone heads fom my 400 sbc would do the trick or if I need it get them redone plus some more machine work
If you plan on running the stock heads with stock pistons that cam is going to be useless you wont even be nere the 9.5 recommend compression ratio for that cam. I would consider getting a head with a 64cc combustion chamber with stock piston that will get ratio up and then cam will be good. The stock 400 heads are 76cc. Either change piston and keep stock heads or change heads and keep stock pistons or go with a little smaller cam like the 280h comp cam.
Well if you dont want to break the bank and want a good bang for the buc i would look at speedpro. Flat tops with a stock head with 76cc should put your compression aRound 9.5
yes, they will. how many cc's are the dish? get me your bore size and piston dish (or relief volume for a flat top), and we can get you a very approximate compression ratio. you're going to want as much as you can get, heres why. using a flat top on a 400 bore size, will usually have a valve relief cut into them if they are aftermarket (like a hypereutectic replacement). this will ultimately do the same thing as making your combustion chamber bigger (which will lower compression). there will also be a deck clearance (piston down in the hole) and a head gasket thickness. by the time you add all this together with a 76cc chamber, the c/r has diminished significantly from the advertised c/r from the piston company. but theres more, the more cam overlap you use (which is what gives you that cool sound), the more cylinder pressure you will bleed off. it won't cost anymore money to get the compression a little higher in most cases, and will make for a more efficient, stronger running engine. youll need to know swept cylinder volume, deck clearance volume, head gasket volume, piston dish/dome volume and combustion chamber volume. check this out if you want to figure out how much compression you'll actually lose as compared to an advertised compression from the deck clearance, head gasket, and piston relief/dish volume. ultimately, the c/r ratio is important, but what is more important than the c/r, is the cylinder pressure.
http://www.carcraft.com/techarticles/ca ... index.html
http://www.carcraft.com/techarticles/ca ... index.html
If you're going with the stock heads you'll want to run a flat top piston, a dome will be too much and a dish isn't enough. If you're getting new pistons you should order a set for using a 5.7" rod and get a set of rods too. The reason I suggest this is that with that large of a cam she needs to turn more rpm to get into the powerband and short 5.565" rods don't like rpm that much. This will help with cylinder wall side loading also. You don't have to get crazy on the rods, just a stock set of rods from a 350 or even 305 with some ARP bolts will take quite a bit of abuse and rpm. I know the pistons for using a 5.7" rod are around $160 a set and reconditioned rods with ARP bolts runs from $110-$130 a set, depending on what rod you want. Don't forget to run a 2800-3000 or so stall to match the cam
As i said and he addex a good point with useing a 5.7 rod. You will have one kickass 406. I wish i could gp back to the cheap parts they always seem to last me.crotchss said:
i thought the connecting rods were the the same in the sbc 350 and 400. What makes the 400 a 406
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