Thread: 454 block with 366 crank &502 heads

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I built this engine wit a 454 block from a 1976 chev truck motor and put a 366 dump truck crank and 396 rods with domed pistons and it ran very well but has a rear main leak and has a coolant leak on the passenger side wondering if there could be some problems with this build. I was told this makes a 427 .

you can use the 502 heads on the older block well i have got a way with it but you need to add the cooling holes in the 427/454 deck lower row and used the 502 head gaskets not the 1976 454 head gaskets. yep what you have is a 427 .many have done this you just use 427 pistons as the CH is not the same as the 454 all 366to 502 gm rods are the same 6.135 .crank 366.396.402.427.are all 3.766

Thanks took it to a machine shop. diffrent from the one that did it originally. They told me there are many things wrong with the engine. To start with it has forged 11.5.1 pistons and they said that the block was bored 30 over but it is 7 to 8 thousands over clearance.they say it sould be 3 to 4 for the forged pistons. which is to much.so i need new pistons.Said it had tripple valve spings in the 502 heads which they say is to much and that it will eat up the hyd. cam.they say they can fix the engine and do a roller cam change with roller rockers and chrome moly push rods and a stud girdle.plus fix rods with new rod bolts for about 4000.00 wondering if that sound right. would really like some help with this it is in my 1969 yenko camaro clone. the motor was just re built 1500 miles a go and took it in because of the water and oil leaks and they found all of this . the first built cost 2500.00 The motor was also balance but had a bad vibration at 65

well send it to me and i will build it rigth .to start with a forged race piston can be run at 004to007.5 or abit more has to do with the use .i would take your stuff and run as fast as you can sounds like they do not know much a 4.250 bore forged race pistons i would never put in at 003 . as for a stud girdle you do not need one for a hyd roller or a small solid roller with iron heads .yes the springs on the heads are to much for your hyd roller cam if thats is the way you go

thanks for the good info and i am going to go get my stuff thanks again

For that price i just about can build you a 496 with hyd roller cam in mark 4 454 block and o port heads all new parts fresh machine work