318 to 340

-
It made it! To the OP, I apologize for getting caught up in the comments. In all seriousness, get your block sonic checked. It has been mentioned already. Will be the only way to truly know. With that said, the myth(?) seems that 72 and earlier blocks are the ones to use. I forget the guy, or the shop, but, he built a 'teener for Engine Masters Challenge. Took it out .120, if I remember correctly.
 
Could have been? Would have to dig through some old mopar muscle mags.
 
To seriously answer your question. You would have to get the block sonic tested to see if there is enough cylinder wall to overbore it that much. Your best chance would be a very early 318 block as they were cast close to the same as a 340 block. Or you could have the block cylinders sleeved and rebore but now your talking big money in machine work. It can be done but it really would not be worth the money.
 
We have one. It's a 68 318 block bored out to a 340. If I remember correctly, it has stock 340 heads on it and a Mopar 484 cam in it. The thing runs awesome. It came in a parts car and the guy told us what it was and we didn't believe him, until we tore it done and sure enough it was a stock 340 bore. We put it in a 68 Dart and beat the piss out of it and it stayed together with no problems really. We had no clue how many miles were on it when we got the motor, but we put about 30k on it, changed the crank bearings once at some point and put it back together. It's not a chance most people would take, but to all you haters out there, it can be done, I have seen it and driven it and I wouldn't hesitate to put it back into another car tomorrow! :)
 
I have a 73 block that I would be willing to bore to 4.00" and turn a 360 crank down to fit the teen block. Good set of worked over 302 heads and put in my Ramcharger. Would Be a good torque motor for it. I would try that over trying to go another .040 on a 318 block.
 
you can buy a scat 3.58 stroke crank...cast or forged to fit a 318/340 mains.
 
70aarcuda said:
you can buy a scat 3.58 stroke crank...cast or forged to fit a 318/340 mains.
Click to expand...
They are available, but I have a few stock 360 cranks laying around already. I think it would be cheaper to grind the mains to fit a 318 block.
 
Moparbaker said:
Now that something interesting has apeared I can't help wondering if a -77 block would do... How thick does the walls need to be? Gee, some guy might be happy when I tell him... He might!
Click to expand...
Yes ive done it, a few years ago.
Guy drives it around in Maine.
4.04 bore, 273 closed heads with 1.88/1.50 mildly ported to 220cfm .470 Schneider solid cam 9.8 comp iirc.
Never runs hot. He was a member here.

Already posted pics on another thread asking the same.

Sorry you have to see the same pic of that 408 6 pac... some just love self felation.
 
gliderider06 said:
I have a 73 block that I would be willing to bore to 4.00" and turn a 360 crank down to fit the teen block. Good set of worked over 302 heads and put in my Ramcharger. Would Be a good torque motor for it. I would try that over trying to go another .040 on a 318 block.
Click to expand...
I fail to see the logic in this... what you would have is a "360" with smaller bearings, smaller main bearing caps and thinner cylinder walls. Where's the advantages?
 
QuickDart360 said:
What is your opinion on the 292/508 mopar cam? I plan to use one in my 360 advanced 4° @ cam per crackedback advice.
Click to expand...
It's actually a decent cam. If you have the intake, convertor, and gear to match it.
 
408 swinger said:
It's actually a decent cam. If you have the intake, convertor, and gear to match it.
Click to expand...
I think I do. Will run a holley strip dominator single plane, 9.5" FTI 3400-3600 stall converter. Also have a 4200 stall dynamic converter but not in car. 3.91's in rear.
 
QuickDart360 said:
I think I do. Will run a holley strip dominator single plane, 9.5" FTI 3400-3600 stall converter. Also have a 4200 stall dynamic converter but not in car. 3.91's in rear.
Click to expand...
That's about exactly what I had in my 70 cuda vert back in the day. Ran like a scalded dog.
 
If it is ground 4 degrees and you have to advance it another 4 degrees it's the wrong cam
you are opening the intake and exhaust too early and closing the exhaust too early- advancing sorta works but is best to use to tell you which way to go on your new better grind
 
I have not heard if mopar cams have any advance built into them. Have heard of comp and other cams do. Crackedback and also rusty have had good results by advancing the 284 & 292 cams.
 
it works to get the intake closed 4 degrees earlier to build dynamic compression
so it depends on your compression ratio and how big a cam to start with
it does not help with gas mileage and opening the intake earlier can give reversion
 
Moparbaker said:
I'm wondering about if there's any use to bore a 318 to a 340 or would the cylinder walls become to thin then?
Anyone who's done that? & how good & reliable would it be for daily use?
Click to expand...
Just buy a r3 block and a 4.25" crank and be done with it. :poke:. Oh... and a six pack.:BangHead:
 
You must log in or register to reply here.
-

Back
Top