318 with 675/318 or 974/360 heads Cam Recommendations

[Scampi]

Hello all.

I just did a thread out here a while ago about a 1972 Scamp 318 with low oil pressure problem.

Well I tore apart that engine and found out what the problem was a plugged oil pickup screen that was also turned up and therefore was sucking air. After taking out the freeze plugs I discovered a hole in a water passage due to massive rusting. So the block was toast.

My brother in-law who has three 69 Darts offered to give me a 318 with model 974 360 heads. I have taken apart the engine and it been bored .060 over with flat Top pistons .070 in the hole. Cylinders look ok and the crank looks good. The crank is .020 over on both the mains and rods.

I have not CC'ed the 974 360 heads to know the volume of them. I do have my original model 675 heads off of the old 318.

This are my questions.

My compression is low. My camshaft is bad so I do need to buy a new cam, lifters and probably pushrods. They are quoting me $325 just to mill a pair of heads .040. Which seems a little high to me.

Do I use the 318 heads or the 360 heads?

Are there any cheap 318 pistons to bring up compression without spending a fortune?

Remember it's been bored .060 already but there is hardly any ware in the cylinders.

This is going to be my wife's car so if it had a tiny rump to it that would be fine.

Currently it is a 318 .060 over, flat top pistons marked "2007" on the inside of the skirt, 904 tranny. I believe that it has a 2.76 rear, I will check tonight. Whimpy 7 1/4 in peg leg. It will have a Edlebrock Performer, 600 Edlebrock Carb and a set of Hooker Headers that my brother in law sold me for $75

I have looked at the camshaft recommendations.

Summit K50052
Comp 20-220-3 250/260 @ .050206/212 .432/.444
Comp XE256
Comp XE262
Voodoo 256
Howards 711381-10 @.050 .208/.214 .479/.494

I tried to find a engine masters video where they tested a stock 318 and then added manifold, Carb, headers and a XE262 cam and make 282 HP but I have not been able to locate it. Anyone have a link?

We want to be able to have enough torque to do a burnout. If that is possible with this combo.

Thanks everyone for all of the help that I have gotten so far from you on this site. It is truly amazing the amount of knowledge on here.

Eric


P.S. Here are some Pics of the Junk block, The new to me block and the .060 over piston sitting .070 in the hole.

 

[yellow rose]

.070 down the hole is a bummer. It's worth it to try and find some Pistons to get that up to the deck.

The worst thing you can do is kill compression and then put a cam to it.

I mean, you can deck .070 off the block but no way will you not have to mill the intake manifold to fit. Then the $$$$$ just start adding up. And that's way too much money to take .040 off the heads. In reality, with the piston that far down the hole, the .040 off the heads is like pissing in a river. You are better off just cleaning up the heads and decking the block.

 

[67/6barracuda]

360 heads without milling, save that $300+ For better pistons KB167’s perhaps. Both those comps are mild I run the Xe256 right now more torque under the curve compared to the Xe262 nicer driver cams. I would go as big as those heads would allow if your going to give it that compression. That Howard’s you suggested might work but getting a little big for stock heads. But I’m just a shade tree mechanic at best let the mopar gods get you more detailed input.

 

[Scampi]

360 heads without milling, save that $300+ For better pistons KB167’s perhaps. Both those comps are mild I run the Xe256 right now more torque under the curve compared to the Xe262 nicer driver cams. I would go as big as those heads would allow if your going to give it that compression. That Howard’s you suggested might work but getting a little big for stock heads. But I’m just a shade tree mechanic at best let the mopar gods get you more detailed input.

That is a pretty good suggestion on the pistons. About $365 to get the compression up to maybe 9.2 to one with 68 CC heads. I don't know what thickness head gasket that they are talking about.

So the XE256 cam has some pretty good torque to it then? Any lope to it at all or is it dead smooth?
Thanks for your response back.

 

[67/6barracuda]

That is a pretty good suggestion on the pistons. About $365 to get the compression up to maybe 9.2 to one with 68 CC heads. I don't know what thickness head gasket that they are talking about.

So the XE256 cam has some pretty good torque to it then? Any lope to it at all or is it dead smooth?
Thanks for your response back.

It has a very noticeable lope when cold. When it warms up it’s just enough to tell it has a Little cam in there. Mine is in a 360 with 318 heads. It’s a mismatch junkyard combo, but it runs great till 5k which is good enough for me at the moment until I get my trans rebuilt, throw in a 3k stall converter, and throw on the blended j heads. Then it’s going to want more cam.

 

[gliderider06]

Given the circumstances, I would use the 975 heads and give it a 318willrun home head porting and have a machine shop do a good valve job, new springs and take a few thou off them to ensure they were flat.
Of your options of cams, the old Comp with the 250/260* or a factory 360 cam?

 

[Scampi]

It has a very noticeable lope when cold. When it warms up it’s just enough to tell it has a Little cam in there. Mine is in a 360 with 318 heads. It’s a mismatch junkyard combo, but it runs great till 5k which is good enough for me at the moment until I get my trans rebuilt, throw in a 3k stall converter, and throw on the blended j heads. Then it’s going to want more cam.

It has a very noticeable lope when cold. When it warms up it’s just enough to tell it has a Little cam in there. Mine is in a 360 with 318 heads. It’s a mismatch junkyard combo, but it runs great till 5k which is good enough for me at the moment until I get my trans rebuilt, throw in a 3k stall converter, and throw on the blended j heads. Then it’s going to want more cam.

 

[Scampi]

Thanks for the video. That xe256 cam sounds real good to me and should work well. I will try doing the backyard port job on the head with new springs installed.
Dingle ball home, new rings, bearings, block clean and a gasket kit and should run fairly well. I will probably decide exactly what will order tomorrow and get it from Summit.

 

[Ottmundr]

Hello all.

I just did a thread out here a while ago about a 1972 Scamp 318 with low oil pressure problem.

Well I tore apart that engine and found out what the problem was a plugged oil pickup screen that was also turned up and therefore was sucking air. After taking out the freeze plugs I discovered a hole in a water passage due to massive rusting. So the block was toast.

My brother in-law who has three 69 Darts offered to give me a 318 with model 974 360 heads. I have taken apart the engine and it been bored .060 over with flat Top pistons .070 in the hole. Cylinders look ok and the crank looks good. The crank is .020 over on both the mains and rods.

I have not CC'ed the 974 360 heads to know the volume of them. I do have my original model 675 heads off of the old 318.

This are my questions.

My compression is low. My camshaft is bad so I do need to buy a new cam, lifters and probably pushrods. They are quoting me $325 just to mill a pair of heads .040. Which seems a little high to me.

Do I use the 318 heads or the 360 heads?

Are there any cheap 318 pistons to bring up compression without spending a fortune?

Remember it's been bored .060 already but there is hardly any ware in the cylinders.

This is going to be my wife's car so if it had a tiny rump to it that would be fine.

Currently it is a 318 .060 over, flat top pistons marked "2007" on the inside of the skirt, 904 tranny. I believe that it has a 2.76 rear, I will check tonight. Whimpy 7 1/4 in peg leg. It will have a Edlebrock Performer, 600 Edlebrock Carb and a set of Hooker Headers that my brother in law sold me for $75

I have looked at the camshaft recommendations.

Summit K50052
Comp 20-220-3 250/260 @ .050206/212 .432/.444
Comp XE256
Comp XE262
Voodoo 256
Howards 711381-10 @.050 .208/.214 .479/.494

I tried to find a engine masters video where they tested a stock 318 and then added manifold, Carb, headers and a XE262 cam and make 282 HP but I have not been able to locate it. Anyone have a link?

We want to be able to have enough torque to do a burnout. If that is possible with this combo.

Thanks everyone for all of the help that I have gotten so far from you on this site. It is truly amazing the amount of knowledge on here.

Eric


P.S. Here are some Pics of the Junk block, The new to me block and the .060 over piston sitting .070 in the hole.

View attachment 1715335232

View attachment 1715335234

View attachment 1715335239

Here's what I put in my little 318 when it had about 125,000 miles, and I managed to DESTROY the pegleg 7 1/4 with 2.76 gears in about a year of daily driving;

Lunati 10200701 cam (the one you listed) This was the biggest cam I wanted to go with because of the presumably shitty compression and power brakes.
new timing chain
eddy performer
600cfm summit carb
the 0.039" felpro gaskets
675 heads
pistons were about 0.070 in the hole as well

I got a newer timing chain cover because the new harmonic damper was marked for the newer style.

And fork over the cash for a new harmonic damper, that old one is closing on HALF A CENTURY, that rubber probably isn't much good anymore.

And a metric shitton of advil for my dumbass wrenching while bending over the fenders because I'm not 20 years old anymore.

After all was said and done, I'm guessing I spent around $700 in parts and supplies and beer.

 

[Wyrmrider]

forget the comp xe 256-262-268
lunati has a better line
best 256 is Mike Jones
here is a dino chart bigger motor but torque curve should be similar

 

[383Scampman]

Nothing that has been suggested will work for long unless you clean up the inside of the engine . Soap and water and WD-40 are CHEAP . Milling heads or block to raise compression is not a very good idea IMO. Good pistons are a good idea . Small bores require small valves and ports unless you are racing .

 

[Scampi]

Nothing that has been suggested will work for long unless you clean up the inside of the engine . Soap and water and WD-40 are CHEAP . Milling heads or block to raise compression is not a very good idea IMO. Good pistons are a good idea . Small bores require small valves and ports unless you are racing .

Yes, milling the heads .040 for $325 isn't a good idea. Rather het a set of KB167 pistons for that. I am going to clean the block pistons with a pressure washer, brake cleaner and then WD40 to stop rust. Then paint the block
Freeze plugs are all out. Crank and pistons too.

 

[383Scampman]

Good ! Don Garlits once told me :" The cleanest may not bet he fastest but the fastest will be the cleanest ." Never forgot it .

 

[Scampi]

forget the comp xe 256-262-268
lunati has a better line
best 256 is Mike Jones
here is a dino chart bigger motor but torque curve should be similar
View attachment 1715335576

forget the comp xe 256-262-268
lunati has a better line
best 256 is Mike Jones
here is a dino chart bigger motor but torque curve should be similar
View attachment 1715335576

That is a great looking torque and HP curve. Real flat not peaky.
Which cam was used here? Voodoo 256 or a Mike Jones? Any other specifics on this engine so that we can compare apple's to orange's?

Thanks for the info. As you know choosing "The right camshaft",can be the most difficult part of the building process.

 

[Scampi]

Good ! Don Garlits once told me :" The cleanest may not bet he fastest but the fastest will be the cleanest ." Never forgot it .

That is a great quote and it's so true. I wouldn't have even taken the engine apart if I wasn't going to clean and check everything thoroughly.
If not just put oil in it and run it

 

[yellow rose]

forget the comp xe 256-262-268
lunati has a better line
best 256 is Mike Jones
here is a dino chart bigger motor but torque curve should be similar
View attachment 1715335576

Is that on E10 pump gas? I'd so, that's why the BSFC numbers are what they are. It would be nice to see the BSAC and BMEP numbers of you have them.

 

[nm9stheham]

The KB167's are about the least costly game in town for decent compression ratio. Just one issue..... they are lighter than the stock pistons and will drop about 80 grams off of the stock bobweight..... too much change without a re-balance. Now .060" oversize ones will weight maybe 40 grams more, so that might be juuuust OK. It would be worth a call to KB to ask the actual weight of the KB167 in a .060" oversize. So there is that matter and possible added cost. If you get that actual .060" oversize weight, let us know; I can plug it into my spreadsheet and let you know how much the bobweight has changed.

360 heads are typically 71-73 cc chambers. 675 heads from the 318 will usually be 67-68 cc. Using the larger 360 chambers is like dropping the piston height about .030" and you'll drop a half a point of compression. With your altitude, you need all the compression you can get.

With the KB167's and nominal LA deck height, you get an 8.8 SCR with the 1008 head gaskets at .039" thick, and 91. SCR with the Mr Gasket 1121G head gaskets at .028" thick.

DCR will be decently good 7.5 to 7.7 with the 256 cam. You'll need it with your altitude. At 4000' elevation, it is like dropping 0.8 points of CR at sea level.

 

[nm9stheham]

Here is an alternative for you to maybe get around any re-balance work......

• Use the KB399 domed pistons with are 26 grams heavier, and in a .060" oversize will be getting pretty close to stock weight
• Use the 360 heads unmilled

Now your SCR with a 1008 head gasket is 9.6.... pretty good and will further help with your altitude challenge for dynamic compression. With the 256 cam, the DCR is 8.1 (equal to 7.3 at sea level) so you now can increase the cam to the 262 (or perhaps even a step more) to better use the breathing of the bigger heads .

 

[Wyrmrider]

Jones cam YR I'll check there are some comments on the dino sheet elsewhere on the forum AJ I think
remember this is a 343 AMC with 360 crank
but closest I have a sheet on for Jones cam in a small block I have used this cam in 318 but with much more compression in a 440 it's a motorhome cam
in 318 it's Big as in deep breathing will go 6000 but over the top see the printout
for those familiar with the DC/MP 260 Jones cam is 50% bigger above .275 cam lift- but shorter seat duration measured at .004
OP
did you ever figure your compression with down the hole pistons and 360 heads
usually you can make a low compression Horsepower motor work with gears and rpm for racing but not street-able we did it in stock
but you could burn kerosene
do the pistons
That Howard cam is a great one also but too big for any low end output with low compression
as I said before Lunati Voodoo has more choices in your target cam range
2 motors and neither has a decent cam and lifters?- with your compression even stock duration is too big- there is just no way to build any cylinder pressure
Isky Mile-A more maybe
summit is worse than the comps (well made but obsolete)
If you need a cheap cam get a regrind by someone who knows mopars
nm has some ideas worth considering

 

[MOPAROFFICIAL]

Without reading every reply I do know the last set of 675 heads I pulled off a stock 318 motor cc'd at 68cc.
974 were around 72cc. If you install seats, the chamber volume drops now the valve sits prouder, same for larger valves ,generally. A lot of shops mill .003-.005 unless requested, some charge more if so.
I'd do the 974 heads, 1.94/1.60 bowl/turn work.... oh wait, it's not me... okay, 974 heads with a valve job and .045 milled off them deck and face..
It is possible the 325.00 is a guides knurled, valve job and mill...and you misunderstood or they didnt explain well.. good luck.

 

[Scampi]

Here is an alternative for you to maybe get around any re-balance work......

• Use the KB399 domed pistons with are 26 grams heavier, and in a .060" oversize will be getting pretty close to stock weight
• Use the 360 heads unmilled

Now your SCR with a 1008 head gasket is 9.6.... pretty good and will further help with your altitude challenge for dynamic compression. With the 256 cam, the DCR is 8.1 (equal to 7.3 at sea level) so you now can increase the cam to the 262 (or perhaps even a step more) to better use the breathing of the bigger heads .

Wow.

Jones cam YR I'll check there are some comments on the dino sheet elsewhere on the forum AJ I think
remember this is a 343 AMC with 360 crank
but closest I have a sheet on for Jones cam in a small block I have used this cam in 318 but with much more compression in a 440 it's a motorhome cam
in 318 it's Big as in deep breathing will go 6000 but over the top see the printout
for those familiar with the DC/MP 260 Jones cam is 50% bigger above .275 cam lift- but shorter seat duration measured at .004
OP
did you ever figure your compression with down the hole pistons and 360 heads
usually you can make a low compression Horsepower motor work with gears and rpm for racing but not street-able we did it in stock
but you could burn kerosene
do the pistons
That Howard cam is a great one also but too big for any low end output with low compression
as I said before Lunati Voodoo has more choices in your target cam range
2 motors and neither has a decent cam and lifters?- with your compression even stock duration is too big- there is just no way to build any cylinder pressure
Isky Mile-A more maybe
summit is worse than the comps (well made but obsolete)
If you need a cheap cam get a regrind by someone who knows mopars
nm has some ideas worth considering

Nm9stheham in the comment above yours had a good suggestion. Possibly put in some. 060 over KB 399 pistons with a 1008 head gasket to bring up the SRC to about 9.6 to one. Yes it would add about $320 to the price of the build but don't you think that this 327 ci engine would start to wake up? It really does not make much sense to rebuild a engine for a "Muscle Car" and have it be a total slug. I'm not taking about a non street able drag car but rather a car that will push you back in the seat some and be fun to drive.
Would this Compression ratio need 91 octane fuel? I live at 4000 feet elevation if this helps
We don't have 93 octane gad here so that's out..

Would the Mike Jones 256 cam or the Voodoo 256 cam still be good if the SCR is 9.6?
Thank you and Nm9stheham for taking the time to figure this out for me. I do want to figure this out soon ... in the next couple of days to get the parts ordered and get it rebuilt.

Eric

 

[Scampi]

Without reading every reply I do know the last set of 675 heads I pulled off a stock 318 motor cc'd at 68cc.
974 were around 72cc. If you install seats, the chamber volume drops now the valve sits prouder, same for larger valves ,generally. A lot of shops mill .003-.005 unless requested, some charge more if so.
I'd do the 974 heads, 1.94/1.60 bowl/turn work.... oh wait, it's not me... okay, 974 heads with a valve job and .045 milled off them deck and face..
It is possible the 325.00 is a guides knurled, valve job and mill...and you misunderstood or they didnt explain well.. good luck.

This guy is the only guy machinist in town.I specifically asked how much just to mill a pair of 318 heads .040. Nothing else. He said $325. He charges $375 for a basic valve job with Z28 springs on a Small block Chevy vortec head. Z28 springs ar about $40.

 

[MOPAROFFICIAL]

This guy is the only guy machinist in town.I specifically asked how much just to mill a pair of 318 heads .040. Nothing else. He said $325. He charges $375 for a basic valve job with Z28 springs on a Small block Chevy vortec head. Z28 springs ar about $40.

Yes they're Elgin brand, you can buy the whole kit for next to nothing. Springs ,valves,locks.. all that.
I would rather drive 3 hrs or more than pay someone like that. Crazy

 

[Scampi]

Every major town is about 100 miles from here. But if I can get machining work done for $200 less it would pay to do a road trip. Zero decking the block, etc. If not the pistons may be the best option if one doesn't have to rebalance the engine.

 

[stixx]

Great Falls, Bozeman, Missoula? How do I know? I'm german, but long time ago I went on a road trip
which led us from Glacier Nat. Park to Yellowstone and further, passing Helena. Sorry, OT.