His build is in the 400-650 range, he shouldn't be looking at 10:1 pistons anyway... haha "Bolt on"s will get pretty decent results, maybe not some magic 275 hp number but who care if it is "quick" and fun to drive.
building a mild Daily driver 318
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His build is in the 400-650 range, he shouldn't be looking at 10:1 pistons anyway... haha "Bolt on"s will get pretty decent results, maybe not some magic 275 hp number but who care if it is "quick" and fun to drive.
bigcasey123
Active Member
\the 8 1/4 sounds perfect for my build then
bigcasey123
Active Member
when i said 400-650 range i meant for the heads alnone not the whole build lol
That's what it costs to have heads rebuilt to stock specifications. No porting, no nothing extra.
bigcasey123
Active Member
the motor im looking at now is a 69. that means the compression is 9.2 stock. (i googled it)
how much more compression would thin gaskets give me
how much more compression would thin gaskets give me
Sorry I misunderstood, well depending on the bottom end plans, yes 400-650 for head would be a stock rebuild or maybe a valve size upgrade on a 318 head you already have.
Some porting can be done using the guide in this forum, but to pay someone would easily double that price. I personally think you can achieve your goal on 318 heads (valve job minimum) and bolt on's.
bigcasey123
Active Member
its all good.
and i have a neihgbor who has ported many heads before and is willing to give me a hand. i think ill wait on getting new heads until pretty much everything else on the car is taken care of so ill have the extra $ to get some nice ones
Google? That's hilarious. Google doesn't know squat.
While the "spec" for the compression ratio may be correct, it is certainly not what they came through with.
Chrysler was known for terrible machining tolerances. Very tall block decks, big combustion chambers and so on. So, all that equals much lower actual compression than advertised.
You will be lucky if that engine has an honest 8.5:1.
bigcasey123
Active Member
lol i found a mopar engines pdf on google. that wasnt really my source lol
and thats crazy hat its that far off. i wouldve guessed it to be slightly lower but still arund 9:1
and If you had to guess how much does it cost to get your heads milled
and thats crazy hat its that far off. i wouldve guessed it to be slightly lower but still arund 9:1
and If you had to guess how much does it cost to get your heads milled
Infecteddog
Well-Known Member
I'd readily believe that given what I've seen.
Factor service/performance changes over the years in with that too- there's basically no telling what you'll really see. Just because you see a small port 2bbl on a small block doesn't mean it's a 318 or stock. Some original motors can be even less convincing in their uniformity than a motor that's so mismatched even a rebuilder wouldn't have sent it out their door. Another piece that's usually left out of the puzzle is gasket thickness- I don't think any stock gasket I've seen come off was even near the size of the average replacement. I'd be surprised if most HG changes aren't enough to knock .2 off the CR by themselves.
Buying a good set of (stock) heads, having them redone, maybe a few other valvetrain components if you did well previously, would have no trouble eating that up.
Your compression should be matched with the rest of the build. No sense building a motor that can't quite run pump gas if you just want a no-headaches reasonable motor whatever it makes. What compression you should go after should be very much related to the rest of the build. Closed chambers, larger cams, and aluminum heads allow for higher compression than their opposites will on the same fuel.
318willrun already mentioned what he paid. It's going to depend as prices will not be the same at every shop or in every area.
Machine work varies by location. I just had my Ford 400 heads rebuilt and they were not quite 400 for everything they did. There was no guide work involved, because they were in great shape. In fact, the heads had been already rebuilt and new exhaust guides were installed. The intakes were perfect. However, the heads needed exhaust seats badly, as a few of them were sunk. So, I took them in to get them right. They installed 8 tungsten carbide exhaust seats, milled them .060" and set my valve springs up on them. Had they needed guide work, I could have added another 200 dollars.
It might be to your benefit to check out Allied Cylinder head. They offer reman castings very reasonably. I actually went that route last year, when I replaced the heads on the 351M that is in my truck now. The heads were worn slap out. One burned exhaust valve, they needed all guides and all exhaust valves, plus all exhaust seats. That would have cost a fortune. I got a pair of reman heads for 350 shipped.
I could have done that this time, but these particular heads have better ports and chambers and are hard to find, so I had them re-done.
It might be to your benefit to check out Allied Cylinder head. They offer reman castings very reasonably. I actually went that route last year, when I replaced the heads on the 351M that is in my truck now. The heads were worn slap out. One burned exhaust valve, they needed all guides and all exhaust valves, plus all exhaust seats. That would have cost a fortune. I got a pair of reman heads for 350 shipped.
I could have done that this time, but these particular heads have better ports and chambers and are hard to find, so I had them re-done.
Bigcasey, I'm gonna say this just in plain English: Does your 318 run well? I mean, oil pressure, no smoking or unnecessary noises? No overheating. If all this is well, Just throw a 4bbl, headers, and a 340 size cam in it. If you want to mess with heads, home port what ya got or cut some 360 heads. Complete your project for about 600 bucks. Your set to go. Stop beating your head against the wall over compression. I did EXACTLY what I mentioned above to a 318 in a '76 Dart. It ran 14.40's at 96 mph, with 3.21's and a tight factory stall 727. I'm sure a good 904 with a 2400 stall would have gotten me into the high 13's. Most would count that "mission accomplished" for what was spent on the 318.
Hell yeah what he said. ^^^^^^^
That's the problem when compression comes into the conversation, it turns something that could be done in a couple of weekends and enjoy the car to something that's gonna sit on blocks for the rest of it life.
Start with the basic first and when you run out of things to do then tear into the motor. There's lots of power to be had before you need to tear into the long block. If your gonna do heads wait until you have the money to do it right and buy EQ's or something.
bigcasey123
Active Member
the motor is out of the car and needs rebuilt
Even so, don't get all hung up on compression. Who cares what it has? Are you racin the thing for points and money? Then just do a basic stock rebuild ot the reciprocating assembly, add a mild cam, headers, decent intake and 4 barrel and call her done.
Snake
Mopar Nut
I like HEAD
RAMM
Well-Known Member
Quoted for truth. J.Rob
bigcasey123
Active Member
Sounds like a good idea. I figured thats realitivly close to my goal. i can port the heads with a freind whos done about a dozen heads before as well. and when i get some extra $$$ i can buy and bolt on some new heads it i even want more power. who knows i might be happy just the way it is.
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So if I understand this right, the ActionPlus, and a 600, and a 340type cam, dual exhaust,a valve job on stock teener heads, with the bowls mildly opened up, will make in the neighborhood of 310hp;more power than a stock, brand new 1970 340 engine?
What are you thinking? what did I miss?
With the headers as a plus, you would gain at least 80 horse power over a stock 318. I will tell ya what you missed, a 340 gross horsepower is more than 275, and that's not a secret. Now let me ask you this question: What did a factory 73 340 dartrun the 1/4 in from the factory? Get the numbers, and I will tell you I ran 14.40's at 96 mph with a non posi, 3.21 geared, 727 (stock w/stock converter), with the build mentioned above. Only I had a cast intake with TQ instead of the Action plus, and I had 360 smog heads, which to most folks here I hurt performance using the 360 on a stock block 318. Might I add, the 340 cam I used was a used cam with almost 100k on it, and the heads had much slop in the valve guides
^^^^ that's why I don't get hung up on horsepower. Folks want a certain "horsepower", but have no idea what they want the car to do, or no idea of what goal for an E.T. to run. Just want a number for horsepower.
Infecteddog
Well-Known Member
No, almost certainly not. Much more likely somewhere solid in the low-mid 200hp area. Should be around the place a 302 swap that doesn't see excessive port and head work (enough to buy a Magnum motor) would go. More than that- it's relative. I find it hard to believe the numbers in the 300s would be actual on most builds.
Now gearing and 904 not the same- yeah, it could be quicker than a factory 340 car if it's down a bit of HP or closer to a '73 340. I think it'd run the numbers with the rest of the car around it even if it didn't
The reason I'd think about it the opposite way is I've never had a 2bbl run near as good as a 4bbl, even the ones that were acceptable. Everything before is not too complicated, makes it easier or no more difficult to obtain good reliable consistency from it, and everything before will help some towards the ultimate goal. It'll run a little bit stronger on the topside with just a 4bbl, it'll pull a bit harder with headers, it'll have a stronger sound with the headers, and it'll be easier to make it run near perfect with the 4bbl. Its condition and reliability are primary, then comes the rest. The thing about compression is if you have only the compression and the rest of the build's not there to match, not only will it be about as much a dog- but it won't behave well either or will need higher grade fuel. Been there, done that- won't again. Sure, it's fine to band-aid in a car that only ever has a driver and never really gets beat on- but best case you're gaining nothing or on the worst hand you're losing reliability.
Off-idle's important but the modern performance most are trying to replicate is higher HP and less torque. Steep trans gears and steep gears make up for the lack of grunt the motors themselves possess. Sure, a stock 318 has loads of low-end grunt but if you're not trying to have a yard cart- it doesn't need to keep it all and most given up to gain mid and upper range will be better rather than worse. In a 4800 lb truck, I'd rather give up off-idle if it means a healthy mid-range and there's no reason for any different in a far lighter car with less driveline loss. A meaty bottom end is far less fun than the healthy mid-range it'll cost. Part of the problem is the perfect "torque" build is stock. Not one thing different. 10:1 in a motor with a tiny cam with a small carb and small ports would be a nightmare- it'd be slow, but you wouldn't have the low hassles of a stock motor.
This.. & agree with Snake. Seriously make what you have work, add the right basic budget parts,& tune the snot out of it.. If you need to learn, do it on a budget... The more you learn,the better decisions you make with accumulated experience.. Then you build, more expensive hardware.( JMHO, it works for me..)
Just build it old school like we did growin up. Leave the long block alone. Intake, carburetor, headers and if the budget can allow a mild cam and lifters and new timing chain set. You can also recurve the distributor real cheap.
That 318 will lay it down then.
That 318 will lay it down then.
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