318 to stock 340 power level questions.

[2 Darts]

I realize I will have a port mismatch with the cast iron 340 intake and the 318 heads but it is something I will have to live with.

That's the reason I brought the whole head issue up earlier. The Comp 275 DEH compares well with the more aggressive Lunati. IMO, the 275 DEH would be as aggressive I would go. You have enough your rear gear to go with any of the cams suggested. It's your $s.

 

[A38Valiant]

68 318 is advertised as 9.25 CR with the open chamber heads. Swapping to the 302 castings will yield around 10.2, if what I'm told is correct. Thinking of going this way myself. A friend did this same combo with the Mopar purpleshaft cam, 284/.484. He said "Damn thing ran better than a lot of 340s I've had!" Don't know what his basis for "better" was, being that the 318 was never to the strip or on a dyno. Guess he was just going by feel........:toothy10:

 

[1968FormulaS340]

Little update.

Im going with the build sugested by Moper in post #4, then seconded by rumblefish360 in post #7.

I think this will give me exactly what I'm looking for.

Past weekend got the engine pulled apart. Everything looked good for the most part. Bit of a ridge at the top of the cilinders and a broken piston skirt on #6 (outer side of piston).

Bearings and crank looked normal. Internally the engine looked clean. Valve train looked normal. Cam looked normal. #1 and #2 exhaust valves were discolored compared to the rest.

Going to get the heads in for the work needed and will most likely have the block tanked, checked and bored.

So new pistons are in the picture now.

 

[1wild&crazyguy]

Little update.

Im going with the build sugested by Moper in post #4, then seconded by rumblefish360 in post #7.

I think this will give me exactly what I'm looking for.

Past weekend got the engine pulled apart. Everything looked good for the most part. Bit of a ridge at the top of the cilinders and a broken piston skirt on #6 (outer side of piston).

Bearings and crank looked normal. Internally the engine looked clean. Valve train looked normal. Cam looked normal. #1 and #2 exhaust valves were discolored compared to the rest.

Going to get the heads in for the work needed and will most likely have the block tanked, checked and bored.

So new pistons are in the picture now.

now see this opens up a whole new set of options, no more cam at the mercy of the compression and the rest.
Bump it up to 9.8 or 10.2 and go a lil bigger on the cam, with the bump up in comp you'll be no lesser in the low end torque and the pick up in mid rangle will more than make up for it.
but do what'ch want.

 

[1968FormulaS340]

now see this opens up a whole new set of options, no more cam at the mercy of the compression and the rest.
Bump it up to 9.8 or 10.2 and go a lil bigger on the cam, with the bump up in comp you'll be no lesser in the low end torque and the pick up in mid rangle will more than make up for it.
but do what'ch want.

Im all ears and taking it all in. That is why I made this thread and use this forum.

Lots of ideas from knowledgeable people.

 

[1wild&crazyguy]

look at the comp XE275HL or 275DEH or even XR274HR [hyd roller]
Those are my conservative picks/recommendations assuming you want to stay with a hyd , 9.1-9.5 comp and 3.55-3.91 gears.
all stock la heads, big and small, peak flow around the same lift [.450-.500]ime

 

[69-318]

what are your guys's thoughts about using the keith black 167 pistons and zero decking the block to get some compression? Iv got a 318 magnum I just started to tear down and Iv seen a few builds with these pistons online but wasnt sure if its a good way to go.

 

[green1]

I had a ld4b intake, and only had to grind the ports 1/8" to gasket match a 340 x head.

 

[caferacerx]

68 318 is advertised as 9.25 CR with the open chamber heads. Swapping to the 302 castings will yield around 10.2, if what I'm told is correct. Thinking of going this way myself. A friend did this same combo with the Mopar purpleshaft cam, 284/.484. He said "Damn thing ran better than a lot of 340s I've had!" Don't know what his basis for "better" was, being that the 318 was never to the strip or on a dyno. Guess he was just going by feel........:toothy10:

all flat tappet 318 use the same compression height piston, the early higher comp 69 motor used a 273 type closed chamber head, the later roller cam and magnum motors used a higher compression height piston with close chamber heads to increase comp and create quench

 

[A38Valiant]

all flat tappet 318 use the same compression height piston, the early higher comp 69 motor used a 273 type closed chamber head, the later roller cam and magnum motors used a higher compression height piston with close chamber heads to increase comp and create quench

WRONG!!!! The 67 engine used the closed chamber heads. Heads for all 68 thru 73 318s are same casting number. Also, the 68 and 69 pistons have 4 valve reliefs, and use floating pins. Stop by anytime, I will be happy to show you!

 

[1968FormulaS340]

WRONG!!!! The 67 engine used the closed chamber heads. Heads for all 68 thru 73 318s are same casting number. Also, the 68 and 69 pistons have 4 valve reliefs, and use floating pins. Stop by anytime, I will be happy to show you!

The 68, 318 I just pulled apart did have 4 valve relief pistons, and floating pins.

 

[rumblefish360]

For certainly possible. When is that engines build date again?

 

[1968FormulaS340]

For certainly possible. When is that engines build date again?

Being that this has became a bit of a debate Im not willing to go by my poor memory. As soon as I get back to my friends shop and have a look I will and post all the info and picks.

 

[tekslk]

You can buy 360s any where and it will bolt right in, I just changed my 67 barracuda to one I thought I had a Great 318 but you cant beat cubic inches. I have 72 318 heads in great shape and a summit cam if you can use them 100 bucks but I dont ship local pickup only. call 570-658-7721

 

[1968FormulaS340]

You can buy 360s any where and it will bolt right in, I just changed my 67 barracuda to one I thought I had a Great 318 but you cant beat cubic inches. I have 72 318 heads in great shape and a summit cam if you can use them 100 bucks but I dont ship local pickup only. call 570-658-7721

This thread has a very specific topic and that topic is not about 360s.
You also turned my thread into your own personal For Sale post.

 

[1wild&crazyguy]

oh snap!

 

[1968FormulaS340]

Sorry about that. I guess I was a bit rude there. Just trying to stay on topic for a change. lol

 

[1wild&crazyguy]

Sorry about that. I guess I was a bit rude there. Just trying to stay on topic for a change. lol

don't be sorry, it's your thread, not his.

It bugs me when people do that too.

if you had told him to fk himself 6 ways to sunday, well... that might be different.lol

 

[SoulSurvivor]

Sorry about that. I guess I was a bit rude there. Just trying to stay on topic for a change. lol

I like your car and if it has a fire breathing 340 in it it truly is a sleeper. Have you thought of buying a 2nd Mopar with a 318 to cruise around in and tinker with? It will make you appreciate what you have done with fastback. Maybe a sister car to yours..a 68 Dart Custom 318 or something to that effect. Just an idea.

 

[1968FormulaS340]

I like your car and if it has a fire breathing 340 in it it truly is a sleeper. Have you thought of buying a 2nd Mopar with a 318 to cruise around in and tinker with? It will make you appreciate what you have done with fastback. Maybe a sister car to yours..a 68 Dart Custom 318 or something to that effect. Just an idea.

As much as I would like getting another car, I am at my limit for room. Having the original engine on a stand takes up much less space.

The real problem with my 340 is the compression. My wife just pointed out….. Instead of buying new pistons for the 318, just buy new pistons for the 340. She makes a good point.

But….. Im still building this 318, if for no other reason than I want too.



This car has been calling my name at night. I must resist.

http://portland.craigslist.org/clk/cto/2122831898.html

 

[caferacerx]

WRONG!!!! The 67 engine used the closed chamber heads. Heads for all 68 thru 73 318s are same casting number. Also, the 68 and 69 pistons have 4 valve reliefs, and use floating pins. Stop by anytime, I will be happy to show you!

very interesting, I would like to see that,

 

[sireland67]

I had a 69 d100 with a 318 and it had forged crank, 4 valve reliefs on the pistons and get this a single plane 2bbl intake cast iron from the factory.
This had to be the strangest combo I have seen yet on a 318.
I ran it for a few years until the truck rusted out and sold it to a guy who said it was an exact match to a twin 318 powered boat that he had.