Mopar 350 Stroker

[Racingcowboy89]

Okay Mopar 350 Stroker is new to me? So recently I have discovered that a 1973 Mopar 318 LA engine(white engine block) I bought back in March of this year was used in drag racing. I bought it to build for a Baja truck engine, but I changed my mind and decided I would build it for drag racing instead. The connecting rods are a 6.125 small block chevrolet, the pistons are from Ross with a 1.327 in the wrist pin to top of the piston height, and I am thinking he used a 360 crank 3.58 stroke, which would have put everything at a 9.24 height in the bore, bored the engine .060, with filler concrete in the block. It got me curious what made him tear it down? I have found nothing cracked anywhere on the engine. I'm not sure what he used for a top end.

 

[MOPAROFFICIAL]

Refresh maybe ? What heads?

 

[273]

I don't how it would work with 9.24 height ? That would be like around .359 in the hole.

 

[Racingcowboy89]

Refresh maybe ? What heads?

It beats me I was curious about what if I ran 360 or 340 heads on with the bottom setup of what it would put me for compression ratio/hp & torque?

 

[Racingcowboy89]

I don't how it would work with 9.24 height ? That would be like around .359 in the hole.

There had to be a reason why it was torn down? All I got was the engine block, connecting rods, pistons, and camshaft that's about it.

 

[Racingcowboy89]

If I put a 4.000 Stroker crank in, it put me at a 9.45 in the height of the cylinders.

 

[Garrett Ellison]

There had to be a reason why it was torn down? All I got was the engine block, connecting rods, pistons, and camshaft that's about it.

If those rods are for a 2 inch journal, it would accommodate one of the Molnar 4-1/8 inch crankshafts. That would bring actual displacement to 408.5 ci. It wouldn’t be unusual to deck .085 or so off the block to bring it out to zero deck in this custom of a build.

 

[Racingcowboy89]

If those rods are for a 2 inch journal, it would accommodate one of the Molnar 4-1/8 inch crankshafts. That would bring actual displacement to 408.5 ci. It wouldn’t be unusual to deck .085 or so off the block to bring it out to zero deck.

Would you have been able to use 6.125 Chevrolet small block connecting rods?

 

[Garrett Ellison]

Yeah, sbc 6-1/8 rods are made everyday for journal sizes ranging from regular 2.1 inch SBC all the way down to 1.87 Honda or (IIRC) even smaller Ford Focus rod bearings.

 

[Garrett Ellison]

You’ll need to measure your rod bearing end bores to figure out exactly what it is you’ve got there.

 

[Racingcowboy89]

Yeah, sbc 6-1/8 rods are made everyday for journal sizes ranging from regular 2.1 inch SBC all the way down to 1.87 Honda or (IIRC) even smaller Ford Focus rod bearings.

If I won't have any issues using a 360 crank, Chevrolet small block connecting rods, and those Ross pistons. I would assume that be a heck of a compression ratio and HP/torque rating in that 318 block. Having a Mopar 350 Stroker would be wicked cool to have.

 

[Illahe]

Okay Mopar 350 Stroker is new to me? So recently I have discovered that a 1973 Mopar 318 LA engine(white engine block) I bought back in March of this year was used in drag racing. I bought it to build for a Baja truck engine, but I changed my mind and decided I would build it for drag racing instead. The connecting rods are a 6.125 small block chevrolet, the pistons are from Ross with a 1.327 in the wrist pin to top of the piston height, and I am thinking he used a 360 crank 3.58 stroke, which would have put everything at a 9.24 height in the bore, bored the engine .060, with filler concrete in the block. It got me curious what made him tear it down? I have found nothing cracked anywhere on the engine. I'm not sure what he used for a top end. View attachment 1716488864View attachment 1716488865View attachment 1716488866

Is your 1.327” compression hight from the center of wrist pin bore to the top of the piston? How much has that crankshaft been offset ground for the Chevrolet rod combination?

Interesting combination to say the least.

 

[Racingcowboy89]

Is your 1.327” compression hight from the center of wrist pin bore to the top of the piston? How much has that crankshaft been offset ground for the Chevrolet rod combination?

Interesting combination to say the least.

I don't know about the crankshaft because I don't have one but I would like to use a 360 crank. If I used a Mopar 360 crank the machine shop would have to work their magic in that crank working with those rods and pistons.

 

[Illahe]

I don't know about the crankshaft because I don't have one but I would like to use a 360 crank. If I used a Mopar 360 crank the machine shop would have to work their magic in that crank working with those rods and pistons.

Good luck with your Build. Nice to see someone thinking outside the box.

 

[Garrett Ellison]

Be interesting to know what the actual deck height is too. It would probably need longer rods any way it went with a 3.58 inch crank, even if the crank were offset ground. It could have also possibly been used with a 3.79 inch str, too. Most of those are in Chevrolet 2 inch journal size.

 

[Racingcowboy89]

Good luck with your Build. Nice to see someone thinking outside the box.

Like I said I didn't get a crankshaft with it, until I found out "if the guy did have a 360 crankshaft" in it, used the Chevrolet small block connecting rods, and those pistons. It would been a Mopar 350 stroker which I have never heard before?

 

[Illahe]

Like I said I didn't get a crankshaft with it, until I found out "if the guy did have a 360 crankshaft" in it, used the Chevrolet small block connecting rods, and those pistons. It would been a Mopar 350 stroker which I have never heard before?

I believe there is information on the web that confirms that the 360 Chrysler crankshaft has been successfully offset ground to a Chevrolet rod journal diameter. My recollection is that the modification was successful in the 36O block.

The cast crank has its limits, but 6k would seem reasonable.

 

[Garrett Ellison]

Speedomotive in California used to sell a stroker kit for a 350 from a 318. It used a stock cast 360 crank that the main journals were ground down to 318/340 size. The 360 has a larger main bearing journal diameter than the other LA engines.

 

[Racingcowboy89]

Speedomotive in California used to sell a stroker kit for a 350 from a 318. It used a stock cast 360 crank that the main journals were ground down to 318/340 size. The 360 has a larger main bearing journal diameter than the other LA engines.

It was pretty common then to have a Mopar 350 stroker?

 

[Illahe]

It was pretty common then to have a Mopar 350 stroker?

If a crank could be offset ground to increase stroke hence cubic inches someone has done it.

The attached article is not a stroker, but it will give you a good idea of what camshaft specs and valve diameter will really wake up a small bore build. It’s a very good read.

 

[RustyRatRod]

Heck, just make it easy on yourself and get a 1958 350 B engine. lol

 

[GTX JOHN]

The 360 is 2.81 and the 318 is 2.50.

Is it advisable to cut that much off the main journals?

 

[junkyardhero]

they been cuttin' the mains down on 360 cranks for 340's since jesus was a private.

the chubby rods are a cheap and easy work around to expensive custom rods for the application.

sounds like that engine was spec built for a specific class. be careful trying to replicate it exactly, you may wind up down a rabbit hole-- especially if you don't have the critical components like the crank and top end-- at times, a lot of that stuff was one off custom work.

 

[ch1ll]

Are you measuring piston pin height from top of the piston to top of the pin?

 

[Racingcowboy89]

Are you measuring piston pin height from top of the piston to top of the pin?

That is correct