Since this is my first post, I wanted to start off with a little introduction. I bought my 87 Dodge Diplomat last summer, and road tripped from Denver to Des Moines with it.
You can read more about the adventure here. http://dolmageadventures.com/2012/07/16/the-1k-challenge-or-i-might-be-crazy/
Shortly after I got home I noticed that the coolant expansion tank was full of oil, and I parked it. After kicking around what to do with the car for a couple of months I've decided that I want to use it as a cheap autocross and track day car.
Why, you ask?
Well, because it's different, and because since it's the cop car model it already has the heavy duty suspension, bigger sway bars, trans and PS coolers, and because it's a car I already own, rather than a car I'd have to go out and buy. And since my initial investment was pretty low ($400) I'm not going to get too worried about beating up by using it as a track car.
Since I'm on a fairly small budget I'd like to build a motor that's more on the inexpensive side of things. I'm looking for a build with close to 400whp, good torque, and fairly bulletproof. With autocross and track days in mind I'm looking for something that's going to be able to stay together up to 6k rpm.
I'd like to duplicate the little Mopar that could build which was featured in Hot Rod magazine if I could. Here's the link to the build for anyone who's not familiar with it. http://www.carcraft.com/techarticles/ccrp_0401_mopar_318_engine/viewall.html
I have two blocks that are available to use with the project. One is a 4104230-318 block. I don't believe this is the fabled race block, since it doesn't have the X cast into the front of the block, nor does it have 4 bolt mains. However, it does have flat top pistons, compression ratio unknown. This is a 2v motor that was pulled from a mid-80's Dodge truck. Everything looks good inside the motor, the bearings were still in decent condition, and after a quick reseal the motor would most likely run without any real issues.
The second motor that I have available is the stock motor in the Diplomat. I'm not sure if this is a roller block at all, or what the compression ratio on this motor. Based on what I've read on this site the motor does have the hyper pistons and forged rods, but I'm unsure of the compression ratio.
Due to cost considerations I'd like to avoid zero-decking the block if possible. Which of these two motors will give me the highest compression ratio?
My build plan right now is as follows:
Magnum heads, (stock valvetrain)
Stock pistons and block
Cam, (not sure if I want to use the same cam from the article or if there's something better on the market)
Professional Parts Magnum intake
Edelbrock 850 Carb
Mopar orange ignition
Which of these two motors will have the highest compression ratio when assembled? I'm shooting for 10:5:1 compression if I can get it, or as close as I can come to that number. Initially I'm planning on running the motor on 91 octane, but at some point I'd like to tune it for e85, which is widely available in our area, and many local hot rodders are putting down serious power with.
I plan on driving the Diplomat to and from events, so the motor does need to be semi-streetable. It also needs to stay together, so reliability is a concern.
Thanks in advance for any help.