318\bore its a 318 bored to 4 1/8

[Duster Wedge]

Sorry its a 318 bored to 4 1/8 in. It also has 3" exhaust

[rumblefish360]

A 318 cannot be overbored that much. It would have to have extensive machine work done to it.
The 4 1/8 = 4. 125. Thats a really BIG bore.

[Duster Wedge]

I measured it with a micrometer its 4 1/8 in

[pishta]

with a bore of 4.125 (4 1/8), thats gotta be a chevy 377/400/402 (unlikely, I know...) Even a 383 has a 4.250, so it cant be that, how about a .085 over 340? Were talkin thin cylinder walls! Check the block for a big cast in CID number under the driver side head, cant miss it on a Mopar block.

[Duster Wedge]

IT says 318 0n the block and heads

[rumblefish360]

Somthin ani't right.

[Duster Wedge]

We did have to put a larger radiator in the car,it was running to hot with the stock one.the one in it now is a 3 core with 3/4 in tubes.
Its very frustrating when you dont know what was done to the engine.The price was right $500 .
that engine is coming out this winter,I have a 1964 426 wedge engine thas been rebuildt,we are going to put that in the Duster the 426 is stamped on the block HP with an S over it.

[451Mopar]

Sure it's not a 413 big block? 4-1/8" bore on a 318 small block would have very thin cylinder walls, not to mention that I don't know of any "off-the-shelf" piston that would fit this.

[Duster Wedge]

No its a 318

[sanborn]

Does it have an "X" or "M" cast into the block on the right front corner? Those blocks have 318 markings but have the thicker cylinder walls that will take a 4.125" bore. Of course the "R" blocks will go much further but have only been produced since 1994.

[Duster Wedge]

Yes it has an M on the block

[23T-Wedge]

Just out of curiousity, how much overbore will a late 60's 318 block take???

Bo...(Sanborn)Are y'all going to make the snowball race in December??? How are the bones healing?

Ronny
Waymaker Racing
John 14:6

[DartGT66]

Depends on the thickness of the cylinder walls. They should be sonic checked before serious overbore, but I think .030" or .060" is safe for a moderate engine. I have bored one to stock 340 size (0.13" overbore). It worked, but the cylinderwalls were very thin; once installed a too long timing cover bolt and screwed it right through the wall. Anyway, we patched that hole with a brass plug (!) and used the engine many years. It run low 12's in a very light car.

[sanborn]

DusterWedge- You probably have a "McLaren" block which was the road race block that led to the oval track "X" block. There were quite a few "M" blocks produced in the early 70's. As far as I know they had the 4.040" bore from the factory and the thick main webbing that allowed the Diamond 4 bolt caps to be installed. We used them with a 4.100" bore on an oval track application without problems (we did "O" ring the block due to extreme compression w/methanol). They weren't as good as an "X" because there was not a provision for front oil feeding and the "X" had even thicker walls. You might have some heating problems with street use, pay close attention to that.

23T- Yes, we are back together and racing. The doctor took the cast off on Wednesday, practiced on Thursday and raced on Saturday. Qualified 3d @ 13.21 (pole was 13.19) ran the feature without power steering, was running 2d until the last lap when the car pushed coming out of 4 and finished 3d by about one foot (O Well'). The new frame is a little stiffer than the crunched one. We will go to Dixie 11/12 to race (10 to win) and then the race on 12/4 will end our season. Swapped our dually for a Freightliner (keeps it in the Mopar family) so it looks like we have another winter project (I'm getting too old for this).