318 build help

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72dartswingerrob

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This is my first Mopar build. I have a 72 dart with a 318 and 727 auto. 8 3/4 rear with suregrip 323 gears. I have a Edelbrock performer manifold, Edelbrock 600 carb Shorty headers, dual exhaust. Just looking for a mild Street engine. Have a set of 302 casting heads. Will be doing new bearings and rings looking for piston suggestions I Have a summit 6901 camshaft but not sure if that’s the best option. Would like to be 300 or better horse power but just really want to burn some tires and have some reliability What do you think of this combo? Any help or suggestions would be greatly appreciated.
 
Sounds good, bump cr to 9:1 and maybe some porting

 
Like the 302 Heads, and the 714s are the same castings.

1020161036.jpg


Best factory pistons are the '90 - '91 318 pistons from the TBI Roller engines flat tops, no valve reliefs. So even better than what came stock in '68 - '69 on the factory 230 hp 318s with the valve reliefs.

Need to watch your piston to valve clearance with your cam selections.

Both sets are getting hard to find, both sets sit .040 ths down in the hole.

Aftermarket pistons are available but start at .080 down in the hole.

Mr. Gasket #1121G .028 ths. compressed depth head gaskets for added compression.

Good luck on your build . . .
 
New pistons? Keith Black has a Hyperutecic valve delivered flat top set that can be put at zero deck height.
Cam is fine.
I’d rather long tube headers over the short ones.
 
George Jets said:
Like the 302 Heads, and the 714s are the same castings.

View attachment 1715557854

Best factory pistons are the '90 - '91 318 pistons from the TBI Roller engines flat tops, no valve reliefs. So even better than what came stock in '68 - '69 on the factory 230 hp 318s with the valve reliefs.

Need to watch your piston to valve clearance with your cam selections.

Both sets are getting hard to find, both sets sit .040 ths down in the hole.

Aftermarket pistons are available but start at .080 down in the hole.

Mr. Gasket #1121G .028 ths. compressed depth head gaskets for added compression.

Good luck on your build . . .
Click to expand...
 
The heads I have are actually the 714. I did some bowl blending and polishing decked and 3 angle valve job. I was thinking the Keith Black pistons might be my best bet.
 
rumblefish360 said:
New pistons? Keith Black has a Hyperutecic valve delivered flat top set that can be put at zero deck height.
Cam is fine.
I’d rather long tube headers over the short ones.
Click to expand...
I agree. The short headers are kind of a pain to connect to the exhaust with the steering and starter. But a already have them. Better than stock manifolds right?
 
72dartswingerrob said:
I agree. The short headers are kind of a pain to connect to the exhaust with the steering and starter. But a already have them. Better than stock manifolds right?
Click to expand...
HP 340 manifolds flow real close to shorty's. There is a dyno test article floating around about it.
 
Here is a nice option if you don't want to deal with headers. Manifolds and the big 2.5" exhaust pipe all the way out the back.

Performs Nicely

IMG952019030995103236847.jpg


That is some "Big" pipe . . .
 
72dartswingerrob said:
I agree. The short headers are kind of a pain to connect to the exhaust with the steering and starter. But a already have them. Better than stock manifolds right?
Click to expand...

Since you already have the shorties I wouldn't overly worry about especially at 300hp, long tube headers main benefit is it ability to scavenge, on bigger overlap cams it matters way more.
 
toolmanmike said:
That's the one. Thanks.
Click to expand...

There’s another one out there, they found I think it was a 340 passenger and magnum driver to be the best set of manifolds you could get. It might be the other way around. My cousin use to run them on his stock car.

To me cause of the little hp difference between manifolds it’s either standard 360 Manifolds or long tube headers.

On early A bodies obviously be 273 manifolds or long tube headers.
 
273 said:
There’s another one out there, they found I think it was a 340 passenger and magnum driver to be the best set of manifolds you could get. It might be the other way around. My cousin use to run them on his stock car.

To me cause of the little hp difference between manifolds it’s either standard 360 Manifolds or long tube headers.

On early A bodies obviously be 273 manifolds or long tube headers.
Click to expand...
Yep, something to ponder depending on how hot your powerplant is. A 10 or 15 horse increase on a mild 318 might not justify a $800 set of headers and exhaust to match. My exhaust is near shot so it is time to replace it anyway. (original single system cut and modified to duals.) I have a set of 68 340 manifolds sitting on the shelf. I might put them on depending on what I do with the rest. I am still running the oem 2 barrel on my 318. I do have a LD4B and a 650 AVS2 to go on. Change the cam while I have the intake off? Pull the engine and reseal while I am replacing the cam? Build a 390 stroker out of a roller cam block I have in the garage? Too many choices! LOL
 
toolmanmike said:
Yep, something to ponder depending on how hot your powerplant is. A 10 or 15 horse increase on a mild 318 might not justify a $800 set of headers and exhaust to match. My exhaust is near shot so it is time to replace it anyway. (original single system cut and modified to duals.) I have a set of 68 340 manifolds sitting on the shelf. I might put them on depending on what I do with the rest. I am still running the oem 2 barrel on my 318. I do have a LD4B and a 650 AVS2 to go on. Change the cam while I have the intake off? Pull the engine and reseal while I am replacing the cam? Build a 390 stroker out of a roller cam block I have in the garage? Too many choices! LOL
Click to expand...
Oh I forgot the pair of Speedmaster heads in the basement.
 
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