Building a 318, need help choosing parts.

[Moloko]

Here is the current situation. Im messing with a good original short block in this 72 roadrunner. Originally a 318 2bl. It needs timing chain, cam, and heads. I got a set of heads and the casting number comes up to be 4027596 which references to a 1980-1984 police interceptor. I got a summit cam with the specs;

Camshaft, Hydraulic Flat Tappet, Advertised Duration 262/272, Lift .420/.442, 112 sep.

I also got an orange box electronic ignition and the conversion kit since the car had points when we got our hands on it. I also have a electronic distributer. Car has a 600cfm edelbrock carb, and dynomax headers. 904 trans and 2.73 8.25 rear.

I have two choices for intakes. We have a original 340 iron intake which is on the car now (sucks on the 318 heads that are now on the car) and I have an LD4B intake that we got on a spare 318 truck motor. Which would be better for these heads? I know the 340's would port match, and the LD4b would be slightly smaller, but maybe it would flow better?

[TK]

Originally Posted by Moloko

Here is the current situation. Im messing with a good original short block in this 72 roadrunner. Originally a 318 2bl. It needs timing chain, cam, and heads. I got a set of heads and the casting number comes up to be 4027596 which references to a 1980-1984 police interceptor. I got a summit cam with the specs;

Camshaft, Hydraulic Flat Tappet, Advertised Duration 262/272, Lift .420/.442, 112 sep.

I also got an orange box electronic ignition and the conversion kit since the car had points when we got our hands on it. I also have a electronic distributer. Car has a 600cfm edelbrock carb, and dynomax headers. 904 trans and 2.73 8.25 rear.

I have two choices for intakes. We have a original 340 iron intake which is on the car now (sucks on the 318 heads that are now on the car) and I have an LD4B intake that we got on a spare 318 truck motor. Which would be better for these heads? I know the 340's would port match, and the LD4b would be slightly smaller, but maybe it would flow better?

I would go with the 340 intake, port match it, and you'll be set.
Make sure you cc that motor, it might end up being in the 7's with those heads

[cageman]

Ld 4b, all the way.
and get some compression.
also better gears would really wake it up too.

[TK]

why the LD4B cage?

[cageman]

They work real good on 318's

[TK]

he has 596 big port heads, isnt a ld4b a small port manifold?

[teddy1500]

are you sure that it is a 318? 72 road runners had the 400 as standard. the 340 optinal, someone could have put a 2bbl on a 340, need more gear, and that carb is a little big, I have a 600 cfm on my 318, and I think that a 500 would really help off the line.

[Moloko]

a 318 was available in 72. 318 2bl.

[teddy1500]

in 72 you could get a vin of RM23G2? or RM21G2? never heard of a RR getting a 318 untill 73

[TK]

LD4B???
Isn it a small port manifold?

[Dart 65]

Originally Posted by teddy1500

in 72 you could get a vin of RM23G2? or RM21G2? never heard of a RR getting a 318 untill 73

I agree. If the 318 is your original engine, you've got a RR clone. The 318 wasn't available in the RR until '73. I went through all of my literature and confirmed what Teddy1500 said. There were no 318s available in the RR and 340s didn't come with 2bbls in the US (I've heard of them in Australia, but haven't had any confirmation of that.). The base engine was the 400 with an optional 340.

[mopar_nocar]

is this gonna' be a street ride? strip car? a little of both? you need to decide what you want to get the right idea on the set up.

my experience with the 318s is they like the smaller heads (-675s ported and with the big valves or the -302s either set of valves!) and a dual plane intake. if you plan on going with a converter and gears single plane will work ok.

the LD4B is a single plane intake, right? see the above questions about what you want....but MOST of all get some gears under that thing. 3.23s would be better, 3.50s would make a world of difference....if you are going to the track a lot 3.92s might be in order.

take your heads down to a machine shop that you can trust and have them cc'ed. cut enough to get a 58-62cc combustion chamber. i would guess between .030 to .045 cut. put your gears in and hang on!!!

have fun with it!

sb