Your suggestions please, I am jonesing to build.

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Your stroke is around 3.5, a stock 360 stroke is around 3.58. A 360 with zero deck flat tops and those heads and gaskets would have about 9.5:1 compression. So why yours is so high is strange. You might be able to just swap to different heads and problem solved. But you would have to measure what you have first to be sure.
 
If you call Cometic Directly they will make a gasket for you up to a .120 gasket. You probably need a .080 Cometic makes gaskets from .026-.120 Their number is
(440) 354-0777
 
Change the cam to bleed off the comp.Shoot for 175 and you should bee good.You can also mess with the head gasket but you dont want to get too thick.
I thought I was doing that with longer duration cams, how do I do that? I have put in three different cams now, of course I didn't consult anyone. Any longer duration and I am going to like the street manners even less. Go the other way? An RV cam with high lift and no duration that falls flat on its face at 3500?

Your stroke is around 3.5, a stock 360 stroke is around 3.58. A 360 with zero deck flat tops and those heads and gaskets would have about 9.5:1 compression. So why yours is so high is strange. You might be able to just swap to different heads and problem solved. But you would have to measure what you have first to be sure.
Yeah, that is the odd part for sure, it is .060 bigger bore than a 360, but that shouldn't matter. I wonder if it is due to the location of the ring lands on these pistons?

If you call Cometic Directly they will make a gasket for you up to a .120 gasket. You probably need a .080 Cometic makes gaskets from .026-.120 Their number is
(440) 354-0777
Thank you very much for that information!
 
I would pop off a head and check its volume. Something just doesn't add up here.
 
I would pop off a head and check its volume. Something just doesn't add up here.

Well, just as soon as the snow quits flying, and I want to leave the Challenger outside, I am going to pull the engine, set it on a stand, and do just that. I really enjoy doing it, so it will not be a problem.

In the meantime, tomorrow I am running that 360 to my machine shop and am going to go ahead and build it as a stock "pooch motor." I will throw it in the Barracuda to enjoy, until I get this stroker motor resolved. This thread has been awesome with suggestions and information, but the problem is still a mystery. It may be all very obvious once I yank the heads hopefully.
 
With $$$$ being the biggest issue here, lemme throw this out there....

I have no idea about what it happened in late 2008, but all of a sudden I started seeing all thru 2009, and I will probably lean towards saying that in 2010 there will be ALOT of 1985-1991 Dodge Pickups, Ramchargers, and D250 Vans, some 2wd, some 4x4's in a junk yard near you.....and I bet you can score a COMPLETE 88-91 Roller Cam LA360 for less than buying, modifying, or changing anything on that 340.

Then, buy a PAW 360 Rebuild Kit....for $295 or what ever and freshen that bad boy up and get a nice street Intake/Carb setup and basic ignition...

You'll need a external balance torque convertor for the 360 but you get what I am saying.

my .02
 
Ed - From the sound of this you have been looking for a reason to build another engine. I would have started with backing off the timing to 34 and seeing if that allowed you to run pump gas. Most everything I've seen says mopar smallblocks like 34-36 total, and you're running 38 total with a high compression ratio. Your cranking psi is really high, and a cam with more duration would bleed off some of that pressure. Increasing your volume at tdc would do the same thing (i.e. thicker head gasket, bigger combustion chamber, dished pistons, etc). If $ is truly a concern you could at least try changing the timing first, then pull your heads and start measuring volume and stroke, it won't cost you anything. Good luck on your build.
 
If you do rebuild that 360 put some good zero deck flat tops in there. Don't use those stock dished type replacement pistons or you'll end up with really low compression.

Prine, don't they pour something in those cash for clunker vehicles to ruin the engines before they go to the yard?
 
With $$$$ being the biggest issue here, lemme throw this out there....

I have no idea about what it happened in late 2008, but all of a sudden I started seeing all thru 2009, and I will probably lean towards saying that in 2010 there will be ALOT of 1985-1991 Dodge Pickups, Ramchargers, and D250 Vans, some 2wd, some 4x4's in a junk yard near you.....and I bet you can score a COMPLETE 88-91 Roller Cam LA360 for less than buying, modifying, or changing anything on that 340.

Then, buy a PAW 360 Rebuild Kit....for $295 or what ever and freshen that bad boy up and get a nice street Intake/Carb setup and basic ignition...

You'll need a external balance torque convertor for the 360 but you get what I am saying.

my .02
That is an excellent idea, would love to have one of those. I am kind of "salvage yard challenged" since moving up here to Chicagoland from Kansas. I am going to do some snooping around, thanks.
It would be fun to work with one of these newer motors. Right now though, I have the older ones stacked like "chord wood." :D (bunches of them back home in Kansas)




Ed - From the sound of this you have been looking for a reason to build another engine. I would have started with backing off the timing to 34 and seeing if that allowed you to run pump gas. Most everything I've seen says mopar smallblocks like 34-36 total, and you're running 38 total with a high compression ratio. Your cranking psi is really high, and a cam with more duration would bleed off some of that pressure. Increasing your volume at tdc would do the same thing (i.e. thicker head gasket, bigger combustion chamber, dished pistons, etc). If $ is truly a concern you could at least try changing the timing first, then pull your heads and start measuring volume and stroke, it won't cost you anything. Good luck on your build.

Busted!! You are right, I want to build a motor. Guilty as charged. I don't allow my stuff to detonate (ping) as it is detonating the bearings. It will run at 34, but it is kind of a turd. It is not "Happy" at 34, I like them Happy and it starts getting there at 38. :D

After this thread, I am looking forward to yanking that one out, and seeing what is going on.

It was fun to got back to the machine shop today. They have gotten heavily into the antique marine motor business. They bought out a bunch of old dealers. I saw beautiful 20s Chrysler marine motors with hand crank provisions.

If you do rebuild that 360 put some good zero deck flat tops in there. Don't use those stock dished type replacement pistons or you'll end up with really low compression.

Prine, don't they pour something in those cash for clunker vehicles to ruin the engines before they go to the yard?

I already made up mind, if I buy pistons for this motor they will be the right pin height for a 4 inch crank. LMAO
The machine shop will be calling me with the verdict on this block and crank now, so that will determine what I do with this motor.
If they say it can be honed, and the crank polished or turned, I will put it back together. Little hydraulic cam, stamped rockers, stock valve covers, vacuum advance distributor taxi cab motor.

If it needs bored, I will try to take it .060 to 4.06 and put a new set of RHS heads on it. Totally low compression pump gas torque motor.

Can I just buy that BM flexplate for a 360, with part of it cut off, and use my 340 converter? Or, do I need to add some weights also? I have no, zero, experience with external balanced motors.



CASH FOR CLUNKERS had to all be crushed...there should be no physical remains by now....keep your eyes peeled though...Here is the grille/bodystyle you want to look for:

http://photos2.ebizautos.com/used-1989-dodge-ramcharger-150-3819-883984-1-640.jpg
I hope nobody tears down that thing, it is beautiful. Thanks for the help, I need a trip out to look around. Used to be one of my favorite pass times.
 
If you end up boring it bore it the minimum amount needed so that you have more metal and a stronger engine.
 
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