Let's talk 318/349/390 strokers.

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has anybody purchased one of these stroker kits? was looking at speedomotive web. was curious do i have to buy a different oil pan and do any machine work to bottom end for the crank to clear for the counterweights? Any info??
 
a 4 inch crank will fit the bottom end of a sbm with no mods...

it is your choice of rods that mades the difference....

scat i beam or eagle i beams require no grinding....

a h beam or stock rod will require MINOR grinding for the rod bolt to clear the bottom of the cylinder wall...

if you are buying new rods ....buy the scat 4340 I beam rods..

oil pans clear.....and pickup clear ...
 
Rockerdude said:
Wait, your a slant six guy. 225s have a 3.4 bore/ 4.125 stroke... So...
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dosn't mean i like it... but i am planing on sleeving for a 3.750 piston and ussing a 198 crank with a 3.675 stroke

OR go for cubes and do the bore and offset grind the 225 crank for a 4.475 stroke...lol torque monster
 
1wild&crazyguy said:
349 is gonna necessitate modified stock pistons or custom pistons.$$$

The 4'' crank is pretty cheap, but the 318 bore pistons arent.

Brian did a 318 block to 4'' bore and used the slightly cheaper std bore 360/4'' crank piston if I remember right, MadDart had it/has it.

I thought about the low low comp 318 pistons with a 360 crank,but.....
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Yes Brian did all the machine work on a 318 Based Short Block for me with a 4" Crank and offset bore it to accept off the shelf 4" ish Stroker Pistons. That Combo was 402CI, It was supposed to be a 349CI. I bought the crank new in the box from an old circle track racer guy. He told me the crank was 360 Stroke but Brian found out that it was actually a 4" Crank during the mock up process.
 
Oh and I have a set of those CUSTOM 349 Pistons that BJR did if you need a set. They are back yard style valve relieved. They would work for your set up and they are just laying around here. Get them balanced with your rotating assembly though. They are notched deep enough for a 600+ lift cam.
 
Mad Dart said:
Oh and I have a set of those CUSTOM 349 Pistons that BJR did if you need a set. They are back yard style valve relieved. They would work for your set up and they are just laying around here. Get them balanced with your rotating assembly though. They are notched deep enough for a 600+ lift cam.
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PM sent to you Louis.
 
Mad Dart said:
Yes Brian did all the machine work on a 318 Based Short Block for me with a 4" Crank and offset bore it to accept off the shelf 4" ish Stroker Pistons. That Combo was 402CI, It was supposed to be a 349CI. I bought the crank new in the box from an old circle track racer guy. He told me the crank was 360 Stroke but Brian found out that it was actually a 4" Crank during the mock up process.
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what a time to find that out.lol
 
Mad Dart said:
Yes Brian did all the machine work on a 318 Based Short Block for me with a 4" Crank and offset bore it to accept off the shelf 4" ish Stroker Pistons. That Combo was 402CI, It was supposed to be a 349CI. I bought the crank new in the box from an old circle track racer guy. He told me the crank was 360 Stroke but Brian found out that it was actually a 4" Crank during the mock up process.
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I bought this motor...
 
Well I'm going to build the 349. I have most of the parts for the build already and Louis hooked me up with the custom pistons from a build that never happened a couple of years ago. This will be a fairly mild build that will go in the 65 Barracuda. Not looking for a torque monster and don't plan on turning 7k, just something a little different that has a little more grunt than a 318 can offer and my wife won't be scared to drive and will work with my highway gears and stock convertor. I will start a build thread about it once I get a little time.

BTW does anyone have a part number for the 360 crank with 318 mains?
 
Badart said:
Thanks Mad Dart. $400 from Summit isn't bad I guess. Other than the crank I will just need a cam and timing set and then I will be good to go.
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I have a timing set that has only 3 hours of run time and a brand new tensioner still in the box. I also have a .484 HYD purple cam with 3 hours on it also. The cam came out of the same engine as the timing set.
 
Mad Dart said:
I have a timing set that has only 3 hours of run time and a brand new tensioner still in the box. I also have a .484 HYD purple cam with 3 hours on it also. The cam came out of the same engine as the timing set.
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PM sent. Maybe a package deal. LOL
 
I sold a 360 I had built but now in process of 318/392 stroker with edelbrock heads,air gap and xe275hl cam!Going in 83 D150!Cant wait to see how it runs!
 
1wild&crazyguy said:
349 is gonna necessitate modified stock pistons or custom pistons.$$$


I thought about the low low comp 318 pistons with a 360 crank,but.....
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Not sure if this is what you're saying - but the Silvolite 1279P cast piston is the correct Compression height - 1.645"

I think Badger still make one as well....

I had a 349 that ran 13.2 with 318 heads a while back - running the 282S Magnum comp cam.

Main issue is the cast slugs are a flat top with no reliefs - so Piston Valve clearance can get tight at zero deck.

Basically the 392 makes way more sense...just don't run an Eagle Cast crank.............:banghead:
 
If the mains are the same size within the Magnum cranks (between the 5.2/5.9), What kind of custom piston would that require??
 
the main bearing size in the 5.2 and 5.9 magnums are not the same...

the 5.2 is the same as the LA 318, and the 5.9 is the same as the LA 360.


requires the same piston as a LA motor....as said badger and Silvolite make a piston with the correct pin height...for 318 with 360 (3.58 stroke) BUT they are flat tops with no valve reliefs...so you could be limited in cam shaft size.....custom pistons will fix that problem...
 
Great thread, ive been thinking about the 390 as well, ive read that because the 318 bore is so small any intake valve over 1.88 will give it a shrouding affect being so close to the cylinder wall therefore losing power or just not making what you expect with the big valve heads..so my question to you is when making the 390 does this rule still apply??
 
MoparDemon said:
Great thread, ive been thinking about the 390 as well, ive read that because the 318 bore is so small any intake valve over 1.88 will give it a shrouding affect being so close to the cylinder wall therefore losing power or just not making what you expect with the big valve heads..so my question to you is when making the 390 does this rule still apply??
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The bore size is exactly the same whether its stroked or not so, yes, there is some shrouding with a 2.02 intake BUT all this really means is that the heads will not flow what the flowbench says. However, on a 390 or even a really stout 318 the 2.02 still has its advantages. I'm using 2.02 intake RHS heads on a 390 (.030" over for a 3.94" bore) and notched the top of the bores for more clearance. I chose to match the bore tops to the combustion chamber shape reasoning that eliminating the step would be a good approach in the absence of being able to test different ideas back to back.

All I need to do now is find a head gasket with exactly the same shape...:-k
 
Why in the world would anybody build a stroker 318 at 349 cubic inches, when you could build a stock stroke 360, and have cheaper, bigger engine, with less bore shrouding? Makes no sense
 
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