Thread: 402 119cc heads

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Are the Keith Black FHR pistons, true forge pistons? Are they as strong as a regular forged piston? We are wanting to use a set of -41 pistons in a 396 .060 over big block. Everybody tells us that we want forge pistons.

well there Forged Head Relief piston FHR. yes there true forged pistons there strong

Thanks for the information. I was concerned because they are cheaper that some of the other forged pistons. I ask the man at the speed shop and he wasn't sure if they where forged.
You have answered my question and we will install them in the engine. Thanks again.

I have a 402 that is bored .060 over. I have installed a set of keith black -41cc pistons. The heads that I have are casting#3993820 and are 113cc. The Keith Black -41cc piston hit the head. I called Keith Black and was told that a set of 119cc heads will cure my problem. I have gone to the head casting number sites and found 3946074 should be 118cc, but I could not find a 119cc head casting number. On some sites, the 394074 heads are listed at 113cc. I already have a set of 113cc heads and I really don't need another set.

We want a high torgue engine and was told to avoid the rectanglar ports.

My question is; what is the casting number of 119cc cast iron heads?

Any information will be greatly appreciated.

What is the purpose of the motor and what fuel will you use?

I plan on using premium pump gas. The motor is for an 1973 4x4 Chevy Blazer. We don't plan on doing any serious 4 wheeling, just want something that will do well against most pickup trucks.
We are running 35 inch tires with a 373 gears, so we are just kicking around.

how hard do they hit the head one spot or all over the dome ? this happen with the old close chamber ret port heads hi cr psitons and using them in the smaller chamber close chamber O port heads on the Ex side of the dome i just nip them on the BHJ piston vise and re work the piston dome this is not new deal even the open chamber hi cr domes need to be re worked some times the 781 cast i have seen at 113 cc s the 049 are a 118 cc they say

The heads that we have are 113cc open chamber. The piston hits about an inch from the spark plug hole. The head lacks about .150 " from sitting down on the block, with the piston at tdc.
I called Keith Black piston company and they said that I needed 119cc open chamber heads. This will give me 10.6:1 cr. I have checked the casting #'s on the internet and I could not find the part # for a 119cc.

Originally Posted by slowmo

I plan on using premium pump gas. The motor is for an 1973 4x4 Chevy Blazer. We don't plan on doing any serious 4 wheeling, just want something that will do well against most pickup trucks.
We are running 35 inch tires with a 373 gears, so we are just kicking around.

Pat would know better than I, but I would be a little skeptical about trying to run pump gas with 10.6:1 static compression ratio, particularly with that big lump stickin' up into the chamber and cuttin' off the flame front.

The other thing that won't work too well is the 3.73 gear with 35 inch tires. 3.73's will work fine with 28 inch tires, but you will need 4.88 gears to compensate for the 35's. Matter of fact, with any kind of a cam that will support the whole mess, you'll need 5.13 gears and a 3500 stall converter. You haven't seen "TURD" until you drive a 4WD truck with 35's, 3.73's and a stock torque converter, particularly with the cam you'll have to use with 10.6:1 SCR.

Looks like a totally fubar'd plan to me.

Originally Posted by techinspector1

Pat would know better than I, but I would be a little skeptical about trying to run pump gas with 10.6:1 static compression ratio, particularly with that big lump stickin' up into the chamber and cuttin' off the flame front.

The other thing that won't work too well is the 3.73 gear with 35 inch tires. 3.73's will work fine with 28 inch tires, but you will need 4.88 gears to compensate for the 35's. Matter of fact, with any kind of a cam that will support the whole mess, you'll need 5.13 gears and a 3500 stall converter. You haven't seen "TURD" until you drive a 4WD truck with 35's, 3.73's and a stock torque converter, particularly with the cam you'll have to use with 10.6:1 SCR.

Looks like a totally fubar'd plan to me.

any new iron head or alum can be had with 118+ chamber .the 049 casting are 118 + head stock. you can not cut that much off the dome to get it to fit a smaller head it sounds . as for 10.6 cr. with 94 fuel may work has to do with how big the cam is as for the 35 tires and gears your going to run in low lock ?

Thanks Pat for answering my question about the 049 castings. I know that the 35" tires and the 373 gears will not make this a fast truck. We have this engine and we are going to build it up and then we will put in the gears and tires that will improve the performance.
I know what TURD is because it had a 308 gears with a tired 350. It has a 6" lift that we don't like and will drop it back down and replace the 35" with something better.
As for the original question, I am glad that you answered it. Thanks again, Pat.