Stroking a 318 to a 390

-
70aarcuda

70aarcuda

Master Hoader of SBM
Legendary Member
Joined
Jan 16, 2005
Messages
16,639
Reaction score
5,986
Location
las vegas
Have had these parts for years now. The MP (Scat) cast crank 15 yrs...pistons for 5 years...block for 5 years that I bought from someone else. Couple of years ago I finally bought the rings I needed. The block has cam bearing....and brass freeze plugs in it. I have KB 847 .030 which are the dished pistons and a set of Scat I beams rods.

I was unsure of the block so today, I put the crank in with a couple of main bearing and used one rod/piston to check the four corners of the block as I can see it had been decked. So the block is cut to zero deck for the pistons........

So in my spare time I want to get this short block assembled, not sure about cam...heads and what not....

20200417_150234_resized.jpg
 
To my understanding, they perform very well. I think a fellow member here had one in a 3600 lbs Volare and it ran high 10's in street form.
 
About to find out what one with Eddy heads, Comp XE275HL with 1.6 rockers, air gap, and 750 DP will do in month or two, but hopefully sooner. This started as the
"340 extended cab W150 project" but has been on a steady state of escalation. 3.55 gears, 33X12.50s, NV4500HD. Got 4.10 axles already on hand in case 3.55's aren't enough. No one ever accused us of being sane for some reason...
 
Last edited:
thanks 318willrun! so your agree means I will learn something here? :)
(I added that because Jpar has not put anything here. that will be my only "funning" with ya)
and yes, I try to learn from everybodies discussions here.problem is, can't afford to use all the knowledge!
 
70
figure your compression with the .028 and the around.040 gaskets and range of head cc's , post back
glad everything is fitting together
 
abdywgn said:
thanks 318willrun! so your agree means I will learn something here? :)
(I added that because Jpar has not put anything here. that will be my only "funning" with ya)
and yes, I try to learn from everybodies discussions here.problem is, can't afford to use all the knowledge!
Click to expand...

I hear you on the cant afford the knowledge, Tony has a bunch of that knowledge stuffs too.
 
Wyrmrider said:
70
figure your compression with the .028 and the around.040 gaskets and range of head cc's , post back
glad everything is fitting together
Click to expand...

65 cc head and .038 gasket give me a 9.36 to 1 compression...
That is probably what I will end up with....aluminum head...Speedmaster...
This thing will run on 87 octane gas....lol

I have a set of the CNC speedmaster heads that got maybe half dozen passes on them....will clean them up ......leaning toward SFT camshaft....
 
Last edited:
A good of mine friend built a Poly 318 stroker with that crank. Same dimensions. It had a really nice, flat torque curve that peaks around 450 ft.lbs. Poly A and LA can share some stuff. Figure similar dimensions, your might do as well.
 
My friend may be wishing his could run on 87 octane as well by the time he's done, LOL! We don't know the compression as of yet until it gets back from the machine shop, but with the sum of the parts I inspected when we tore it down, I suspect it's going to be pretty high. He has a few other engines to choose from if this one too radical for his liking, which I actually doubt at this point.
 
Man that crank still sparkles after 15 years? Mine looks like the heel of a boot.
 
Last edited:
pishta said:
Man that crank still sparkles after 15 years? Mine looks like the heal of a boot.
Click to expand...

nothing rust out here in the desert....the crank got cleaned up at the machine shop went it got balanced....spit and shine job....
 
I got another 71 Duster sitting here....and I got a 88 dodge D250 that needs an engine...just tired of stepping over the complete rotating assembly plus the block...we are not racing so we are not breaking anything...so i can move on to crap that i have been waiting to do went i retire ....yeah...retire...lol
 
Like a 318 with good heads is hard to tell from a 340 in terms of performance, the 4" versions are comparable. It will do well in anything with the right heads and cam. But you already know that...lol.
 
Got the crank bolted in today....probably get the rods and piston assembled tomorrow...I had to find a set of spiro locks...as I stole the ones out of this box for something else.
 
.leaning toward SFT camshaft....
lots of good ones
Camcraft lobes will work on a sbc billet(with mopar lifter bores) so they have a big nose on a Mopar- easy on parts
Bullet
Engle has three series of MOPAR lobes easy to race only
Crower (PM Dart19666)
the big guys have problems giving good tech advice and some grind series are more up to date than others
fill this out
Street Performance | Jones Cams Mike give excellent tech advice and has good lobes if they match your needs
 
got the pistons and rods mated...i kicked those spiro locks butt....

the rings are not file to fit....checked a couple...top ring I am getting .018,,,,and second .020....

cast crank does not use narrowed bearing...this thing will be done soon....at least the basic short block
have to figure out what color to paint it......
20200419_101534_resized.jpg
 
You must log in or register to reply here.
-

Back
Top