I accumulated some good parts for my Mopar and I'm starting to play around with some ideas.

I've got a 69 340 bored .030 over with Speed Pro pistons at probably around a 9:5 c/r with the J heads on it. Also has forged Eagle H beam rods and a factory forged steel crank.

I picked up a set of W2 heads/valvetrain and an Indy intake from a reputable forum member a few months back. The heads flow just a hair shy of 300cfm's and they were pushing his A body deep into the 9's. My plan is to run those heads on my bottom end and have a good cam spec'd out to match after figuring out exactly where the C/R is. Simple enough.

Here is where the crazy talk comes in. Over the years I have also accumulated a D1SC procharger/intercooler/bypass valve for the chevy project that I decided to weld up a twin turbo setup for. I also have an Aeromotive A1000 fuel pump and enough 10 and 8AN line to plumb my challenger with. I realized I need very little to set this car up with the Procharger, I'd just have to cut a bracket out, figure out something for a crank pulley adapter and weld up the piping. Top it with a good blow through carb and have fun with boost.

What I am worried about is the block. If I were to do this, I don't think making 650 fwhp would be a problem capability wise, enough power to get me deep into the 10s. What do you guys think about a half fill for a street car? I think making that kind of power boosted will actually be safer on the block than the guys making big power N/A as the RPM's won't be there. Tuning wise, I just need to make sure I am in a very, very safe range. Maybe run methanol injection for safety depending on how low I can get my C/R with the speed pro pistons and a thick head gasket.

With the price of aftermarket mopar blocks, I am definitely not looking to do one now. . I'd love to try to push my small block to Hellcat killer status but I am just wondering what I can do to make it as safe as possible? I'm sure it'll be on borrowed time regardless, but I don't drive it much and it's not a bracket racer so if it lasts me 20k street miles I'd probably be happy LOL

Not sure about you tech questions, but the proposed build is overkill for most Hellcats on stock tires. I beat my first one in my '68 convertible Barracuda with a 410hp Stroked Magnum, a 200R4 and 3.91's on 275/60-15 Nittos.

650 HP will be very low 9's or high 8's unless it's a station wagon or armored tank.

No way would I do that kind of power with boost. The blocks were never designed to take it.

I like what your thinking. I would build it.

What 2400-2500 lb vehicle are you basing this on?

Save the W2s for another build and just procharge what you have.

650hp boosted on the stock block and a half fill will be fine.

Mine has the same with a girdle and makes in the 800hp range single turbo.

Be safe with the tuneup, don't detonate it, and you'll be golden.

Your build looks awesome! Have you had any issues with the half fill and street driving? I am figuring I will have to upgrade the cooling system a bit (thinking aluminum radiator, electric water pump, possibly electric fan). I'f I'm not mistaken, a half fill can be done AFTER machining the block, correct? I only ask because my block is still pretty fresh (maybe 15k miles) so I was hoping I wouldn't have to do any more machine work except for maybe a hone job on the bores.


On the detonation issue, I think you are right about that. I know from my experience with late model chevy stuff, guys started finding the "limits" of the stock LS series engines very quickly and very early on with boost. Funny thing is, fast forward 8 or 9 years and those so called limits are now twice that of what they were when guys first started boosting them. What they thought were the engine's structual limitation was actually just the limits of how much of a poor tune the block could handle. Now that people have become more knowledgable in that area, you are seeing people push stock rotating assemblies well beyond what everyone initially thought they were capable of, and they are lasting years. I plan to run a wideband 02 to keep tabs on everything and use the methanol injection for added safety. Since I won't be trying to run a whole lot of boost, I think as long as I can get my C/R down enough I should be pretty safe detonation wise. I just need to learn a lot more about blow through carbs as I have only played around with boosted late model setups.

72swinger, why do you reccomend not using the w2's? I currently have J heads with a valve job but nothing crazy. I have a dual plane Eddy performer but also have a single plane victor jr in the garage I could use.

I realize that boosting the motor as-is would certainly be an option, but I figured the W2's flow way better than the J heads I have now so I should be able to make more power with less boost (which means less heat and less risk of detonation). What do you guys think? I am really looking to make as much power as I can, but without being too stupid about pushing the limits of the engine I have. The procharger will support 900hp and I figure with the W2 heads I would't have trouble making that, but I figured 650ish would be about the max of the half filled stock block and stock forged crank before things get REALLY risky.

I think you will be at the ragged edge of the block capacity with the J's and the blower is all. Easy to crest the 650 threshold as it is, the W2's will just push it over that. I would say the W2's would be better used on a 600-625hp NA stroker SB, but hey you have them, use them and lower the boost?

It's a terrible idea (that should be vigorously pursued)

NA power eats blocks due to rpms
Nitrous eats blocks due to detonation and rich tuneups.
Blowers eat blocks due to hp the crank sees to overcome power to turn blower.
Turbos are the easiest on bottom ends due to the pressure being against the piston all the time.

I would love to see you take a stock block with a 600hp combo and add 200hp in boost. The best main caps and safe tuning are a must.

You've got a point. I am guessing I could make up to the limits of the block with the J heads I have and a little more boost. I'd love to keep them for a resto/R block build someday and try to make closer to 900hp with the blower, but at that point it is probably dumb using W2's with the amount of head bolts and with the price of aftermarket blocks I don't know if I would even want to bother with keeping the small block.

I am considering selling them to help fund the blower project. I'll probably use them if I can, but if things look like they are going over budget, maybe I'll sell them.

I am considering selling them to help fund the blower project. I'll probably use them if I can, but if things look like they are going over budget, maybe I'll sell them. [/quote]

Boosted motor and budget dont really go hand and hand just saying im on my second boosted build and im already over budget but lucky when i setup the toad the first one I over killed in alot of area's knowing i was going to go bigger in the future.
Word of advice do your homework and dont buy any parts till you know exactly what your going to need.
As for blowthru carbs you can use the hanger18 mods for lower boost but once you start turning the boost up things get tricky at about 12-15 psi
Good luck

Oh yea, I agree with that statement. This isn't my first blower build, but it is my first one on a carbbed Mopar. Previously I owned a procharged 383 LT1 caprice and and I have been doing a build on a twin turbo 396cid LT1 96 Impala that has dragged on for 8 years. On that build I have been trying to do everything the right way so to speak and also didn't really leave anything untouched (full frame off resto, boxed chassis, notched frame, late model corvette brakes etc...) It has dragged on way too long but is coming out great.

With the challenger, I'm not looking to build a time bomb, but I also think that some corners can be cut if I pick the right ones. Not looking to push this setup too far, I won't really need room to grow because I don't think I'd ever keep the stock block if I wanted more power. Just want to try for 650hp at the motor which I think shouldn't be too difficult given that these heads didn't make a whole lot less than that on the last N/A build they were on.

I just bought what he was pretty sure is an SDCE brand procharger bracket/tensioner assembly for a small block mopar from SpareParts so I guess the project is on.

Going to start test fitting it when it comes and see if I can get the correct crank pulley/adapter from SDCE to make it all work.

Once I can get the blower all fitted up, I am going to decide if I want to move forward and pull the motor to prep it for the blower or put this aside and try to finish the Impala project first then come back to this in a year or two.


I think I will go for a CSU carb as I am thinking that is a good place to spend a little more money. Going to try to do the rest on spare parts I already have or parts I can find used.

What do you guys think as far as the engine goes? I have heard from a few boosted mopar guys that a half fill, factory forged crank, good rods/pistons and good head gaskets (maybe MLS?) would be all that is needed for the 10-12psi or less I'll need for 650hp. Think the half fill is necessary? Skipping it would save me a lot of cash in the motor and in upgrading the cooling system but I don't know too much about the limits of these blocks. I do know that with boost, good tuning can make the difference between a block failing at 900hp or 600hp so with the CSU carb and wideband I hope I won't have problems there.