360 crank in 318 block

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whitepunkonnitro said:
Not exactly sure of the year range, but I do have a set from a 67 318 I tore down a while ago.
I know for certain that by 70 they got away from those valve reliefs.
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OK, yes the older 318 pistons... my '68 273 pistons came right up to the deck too and had eyebrows; IIRC Pishta has a set too. Those engines had CR's that truly were up in the 9:1 range. I believe they got away from that with the earliest emissions requirements around '71-'72, maybe the same changes that prompted the low CR 340 version.
 
I got a 360 crank with turned down mains. did the math a while ago and I still got a positive deck height with a teen but a .040 head gasket would totally cover it. Its the piston skirts you need to watch where the throws ride. Dont know if my throws were cut. Its rusting in the shed with a FedEx chipped bolt flange.
 
50377251_L_10759e54-d4c9-4014-84c7-05ae79421bd6.jpg
Not much skirt to cut on many new performance pistons
 
gliderider06 said:
How hard is it? I know to have the mains cut to the 318 size and have rebalance. I have 2 sets of 318s that have the pistons way down in the hole one more than the other. Could I use those on the 3.58 crank? I can measure how far down they are tomorrow. I was thinking of this (already have a 360 crank that needs to be turned) and putting it in my 88 roller block for my Ramcharger. Thinking of doing things, and the squeaky wheels are turning in my head, while I'm recovering from my knee surgery.
Is it really hard to do?
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Indy cylinder head used to bore the 318 blocks out to 4 in and put a 4in stroker crank in them. I asked them about that and they said basically what they did was ultrasound the blocks to find good blocks and bore them out to 4 in.
So what I have been thinking about doing is ultrasounding some of my 5.2s and boring one out to 4in and cutting the mains down on a 360 crankshaft and making me a 360 in a 5.2 block and use the roller cam and whatever heads I have laying around.

simply put you would just be taking the rotating assembly out of the 360 cut the main bearing size to 318 size and boring to 4 in.
There wouldn't be any rebalancing there wouldn't be any block grinding aside from the boring of the cylinders.
This would just be for fun. So if those people looking under my car and see it says 318 are going to wonder why it runs a little bit better.
 
like your thinking Jad
reminds of our AMC that was supposed to be 305 but based on a 360 block (stock bore 4.080) with a short stroke
block said 360 allright but was actually a 428- go ahead- climb under- check the number :)
 
If you do that, Jad, would you mind posting your wall thickness findings? I'd like to see the variations you find.
 
Jadaharabi said:
Indy cylinder head used to bore the 318 blocks out to 4 in and put a 4in stroker crank in them. I asked them about that and they said basically what they did was ultrasound the blocks to find good blocks and bore them out to 4 in.
So what I have been thinking about doing is ultrasounding some of my 5.2s and boring one out to 4in and cutting the mains down on a 360 crankshaft and making me a 360 in a 5.2 block and use the roller cam and whatever heads I have laying around.

simply put you would just be taking the rotating assembly out of the 360 cut the main bearing size to 318 size and boring to 4 in.
There wouldn't be any rebalancing there wouldn't be any block grinding aside from the boring of the cylinders.
This would just be for fun. So if those people looking under my car and see it says 318 are going to wonder why it runs a little bit better.
Click to expand...
I like the way you think.
 
Jadaharabi said:
Indy cylinder head used to bore the 318 blocks out to 4 in and put a 4in stroker crank in them. I asked them about that and they said basically what they did was ultrasound the blocks to find good blocks and bore them out to 4 in.
So what I have been thinking about doing is ultrasounding some of my 5.2s and boring one out to 4in and cutting the mains down on a 360 crankshaft and making me a 360 in a 5.2 block and use the roller cam and whatever heads I have laying around.

simply put you would just be taking the rotating assembly out of the 360 cut the main bearing size to 318 size and boring to 4 in.
There wouldn't be any rebalancing there wouldn't be any block grinding aside from the boring of the cylinders.
This would just be for fun. So if those people looking under my car and see it says 318 are going to wonder why it runs a little bit better.
Click to expand...
if ya cant quit get to 4.0 on bores, silv-0-lite 1278 pistons for a 318, available in .020,.030,.040 and .060 over bore for 318. i looked and couldnt find it in 4.0! i got a la roller 318 im scrounging up for a build on id be interested in how yours gose!!
 
dirty white boy said:
if ya cant quit get to 4.0 on bores, silv-0-lite 1278 pistons for a 318, available in .020,.030,.040 and .060 over bore for 318. i looked and couldnt find it in 4.0! i got a la roller 318 im scrounging up for a build on id be interested in how yours gose!!
Click to expand...
Yes, the pistons would end up about .030 in the hole with these truck pistons. No eyebrows so that will restrict cam duration/lift; your'e gonna end up with about .080-.100" less P-V clearance than the pre-1970 stock 318 pistons that were at zero deck, and around .200" less P-V clerance than a typical performance oritented flat top or domed pistonat zero-deck. So get your Dremel and marking pen out! I found this discussion in that regards:
318 stroker - Piston itch....

Bobweight is going to be within 20 grams or so of stock 360LA bobweight so this can conceivably run without any balance re-work for many/most uses.
 
nm9stheham said:
Yes, the pistons would end up about .030 in the hole with these truck pistons. No eyebrows so that will restrict cam duration/lift; your'e gonna end up with about .080-.100" less P-V clearance than the pre-1970 stock 318 pistons that were at zero deck, and around .200" less P-V clerance than a typical performance oritented flat top or domed pistonat zero-deck. So get your Dremel and marking pen out! I found this discussion in that regards:
318 stroker - Piston itch....

Bobweight is going to be within 20 grams or so of stock 360LA bobweight so this can conceivably run without any balance re-work for many/most uses.
Click to expand...

You could have the pistons eyebrowed for P-V clearance, no big deal
 
nm9stheham said:
Yes, the pistons would end up about .030 in the hole with these truck pistons. No eyebrows so that will restrict cam duration/lift; your'e gonna end up with about .080-.100" less P-V clearance than the pre-1970 stock 318 pistons that were at zero deck, and around .200" less P-V clerance than a typical performance oritented flat top or domed pistonat zero-deck. So get your Dremel and marking pen out! I found this discussion in that regards:
318 stroker - Piston itch....

Bobweight is going to be within 20 grams or so of stock 360LA bobweight so this can conceivably run without any balance re-work for many/most uses.
Click to expand...
any high lift cam needs P-V clearance checked and some times need eye brows cut, them siv-0-lites might need skirt clearanced also! any performance build needs a good balance!
 
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