65 Barracuda AutoX

Is there any way to destroke a 318 or 360 down below the 5100cc limit?

singleslammer wrote: Is there any way to destroke a 318 or 360 down below the 5100cc limit?

The 273, 318 and 340's all shared the same 3.31" stroke. The only difference is bore. The 273 has a 3.65", 318 is a 3.91" and 340 is a 4" bore, so really there is no way to destroke these motors. The 360 has a 3.58" stroke with a 4" bore. You can actually make a 273 make good power, but it takes deep pockets. 7,500 rpms and 450 hp sounds good. http://www.youtube.com/watch?v=x4QKHtP63Bs

Badart wrote:

singleslammer wrote: Is there any way to destroke a 318 or 360 down below the 5100cc limit?

The 273, 318 and 340's all shared the same 3.31" stroke. The only difference is bore. The 273 has a 3.65", 318 is a 3.91" and 340 is a 4" bore, so really there is no way to destroke these motors. The 360 has a 3.58" stroke with a 4" bore. You can actually make a 273 make good power, but it takes deep pockets. 7,500 rpms and 450 hp sounds good. http://www.youtube.com/watch?v=x4QKHtP63Bs

So...can you just punch out the 273 to 305?

What about a 360 crank in your 273

Well the motor is back together. Fresh 318 heads and a holley street dominator intake that I had laying around. It has the smaller 318 runners and should work decent for the time being. I rebuilt the carter afb, I can't recall the cfm, but it came from a factory big block car and ran well on the car before. I have also upgraded the points ignition to an electronic unit that doesn't need an ignition box. I have also junked the factory single master cylinder and gone to an aluminum dual and installed a disc brake prop valve so I can run 73+ spindles. The 273 ain't pretty, but should run decent.

singleslammer wrote: What about a 360 crank in your 273

The issue with that is the mains would have to be turned down. The 360 used larger mains. Guys have done this in 318's to make 349 ci stroker, but makes for a weaker crank, so I have heard.

I have started to mock up the suspension and see how much drop that I can get running QA1 DS401 single adjustable coilovers, 400lb 9" springs.

I should be able to get about 2" of drop and still have about 1" of compression at the coilover which should give me about 2" at the wheel before contacting the bump stop and allow clearance at the fender without trimming. I plan on running 17" wheels on this car with the widest tire that I can run without any trimming.

Here is some car porn for you These wheels and tires are only for rollers currently.

By the way, this build is AWESOME!

singleslammer wrote: By the way, this build is AWESOME!

ST_ZX2 wrote: So...can you just punch out the 273 to 305?

I have never heard of anyone doing this. There is a ton of meat in the block, but finding pistons to work may be the challenge.

Badart wrote:

ST_ZX2 wrote: So...can you just punch out the 273 to 305?

I have never heard of anyone doing this. There is a ton of meat in the block, but finding pistons to work may be the challenge.

What bore gets you to 305 CID? I know that there are pistons that are 3.800"--Oldsmobile 307 for example. Not sure if they are anywhere close to the Mopar bits, but stuff around that bore should be out there.

ST_ZX2 wrote: What bore gets you to 305 CID? I know that there are pistons that are 3.800"--Oldsmobile 307 for example. Not sure if they are anywhere close to the Mopar bits, but stuff around that bore should be out there.

I would have to do some math and talk to my machinist, but it is something to consider. This would also help with valve shrouding.

Here is a pic of the Enkei wheels that I plan on running now. Don't pay attention to the truck tires that are mounted on there. I have a set of 215/45-17 Goodyear Eagles that I will mount for now on the front and 235/45-17 on the rear. I don't want to do mini tubs if I don't have to. Don't worry about the rust in the rear quarters. I plan on welding in new skins over the winter. In the past someone has flaired the rear quarter, which I kind of like and will stay but I will fix what they didn't do properly.

Man those rotors look tiny in there, so I plan on upgrading to Cordoba Rotors which measure at 1" vented by 11.75" and go with these 4 piston wilwood calipers. This should also knock off 20 lbs of unsprung weight. The rear will eventually be converted to disc brakes, but isn't a big concern now.

I'm really enjoying this. It makes me miss the '67 Belvedere II that I drove in high school. I would have loved to have done any of this stuff to that car.

Awesome build!!!

welcome to GRM from the pt duster guy. nice to see an early a build going on here. im still thinking about your strut rods, by the way.

on a side note, can i buy your commando valve covers from you?

Badart wrote: Here is some car porn for you These wheels and tires are only for rollers currently.

That tubular structure that attaches right above the lower control arms and goes back to the firewall. Is that fender brace or ???

Also did you strengthen the shock mount or is that top mount strong enough since they didn't originally have the load of springs on them?

I think I read that Mopar used destroked 340's for Trans Am, coming out to around 303.

You can do that when you have cubic money.

Badart wrote:

Mind if I ask where a regular joe would find some of these bushings/bungs you're using? Or are you just making your own?

I need to do some trailer work and want to add a few well-placed bungs for tie-down bolts and the like.

And yes...this build is really neato!

Thanks! Clem

Dusterbd13 wrote: welcome to GRM from the pt duster guy. nice to see an early a build going on here. im still thinking about your strut rods, by the way. on a side note, can i buy your commando valve covers from you?

Yeah I remember your build thread over at FABO. I'm getting a little sick of Joey's crap. Nice duster btw.

93EXCivic wrote: That tubular structure that attaches right above the lower control arms and goes back to the firewall. Is that fender brace or ??? Also did you strengthen the shock mount or is that top mount strong enough since they didn't originally have the load of springs on them?

Actually the area is fully boxed with the coilover hoops. I know what you are saying about the inner fender area now taking the weight. There are a few companies like RMS and Magnumforce that make aftermarket K members and coilover conversions that have the front frame rails now support the weight of the front of the car. The coilover hoops allow the weight to be transferred down to the frame rails and it triangulated to the firewall. This is more than I have seen some guys run on the street and they claim no issues. If I were building another drag car hanging the front end then I would do something different. If I eventually install a cage in the car then I would run snout bars through the firewall and tie them into shock mounts with landings.

ClemSparks wrote: Mind if I ask where a regular joe would find some of these bushings/bungs you're using? Or are you just making your own? I need to do some trailer work and want to add a few well-placed bungs for tie-down bolts and the like. And yes...this build is really neato! Thanks! Clem

I machine them myself