The car is a 1970 Challenger

The twist being this is kind of uncharted territory as far as the setup goes and I have no idea about what kind of power I am going to be able to safely make.

Here is the setup:

Motor-
'69 340 bored .030 over, half filled block, main studs, head studs, factory forged crank, Speed Pro forged pistons, Eagle H beams, cometic head gaskets. Going to try to shave the pistons down to shoot for a 9:1-9:5 C/R. Topped with a D1SC procharger and front mount intercooler.

W2 econo iron heads ported out flowing 299cfrm at .600 lift with an Indy 360 ported manifold- ran mid 9's in an all motor 408ci A body at 2800lbs.

Cam my machinist is still spec'ing out but it is going to be a big duration solid roller, I am guessing somewhere in the 250 int duration range

Motor will be topped with FItech 8 fuel injection, MSD billet distributor with timing controlled via the FItech unit, MSD 6AL box, TTI 1 7/8ths headers and 3" exhaust. Fueled by an Aeromotive A1000 pump.

The whole setup will run on E85 corn juice. The car has a built 727 and 4:10 8 3/4 rear. I have a spare rear so I am going to push it till it pops and then upgrade to something like a Dana 60.

Battery relocated to the trunk with 15 gallon cell. The car has no AC, no power windows but does have power steering. sub frame connectors, light weight weld prostars with skinnies up front and p295/55/15 Micky Thomspon E/T streets out back. Super stock leafs, lakewood 70/30 drag shocks up front and KYB 50/50 drag shocks out back.

No idea on weight, no real idea on power either. I was hoping to try to run as much as 12PSI thinking that it would make somewhere around 700hp at the crank. I may run a different combination of pulleys at first to keep the whole thing a little safer while I work out the kinks. I'm hoping that even at lower boost levels though I should be able to make 650hp without too much trouble?


take a guess! I should be getting the motor back from the machine shop in two weeks and I am going to work hard to get it all running before fall ends. Think there is any chance of this car going very high 9's (or having the power potential with a bigger tire/better setup up chassis)? May be a stretch but just wondering.

Not sure you are going to see 9's. you are probably going to have to tune the suspension/timing and carb before you get it to et consistently. You might do better w/ less gear. (3.91's) 700hp out of a 340 is going to be tough. I'll guess w/o boost you'll be around 400 and with 12lbs of boost you might see 600 if that.

I would shy away from shaving tops of pistons on a power adder car. That is weather it's nitrous, supercharger or turbo.

With that combo at 12 lbs of boost you will accidentally make 650 crank hp, but I wouldn't run too much duration and keep your overlap to a minimal. Get a blower specd cam. Supercharged cars tend to like gearing just as N/A, so your gears will be fine. Assuming your weight will be somewhere around 3500 lbs, you will be close to high 9's.

Mr. Yuck, I hear you on the tuning part. I am sure I will get nowhere near the times I want until after a lot of tuning, both engine and chassis. As far as the N/A power, I may be dreaming but I really thought I'd be starting with more before boost. The heads I have flow just a hair under 300cfm and pushed a 2800lb A body into the mid 9's. That was on a 408cid motor with high 10 compression ratio, but with that E/T we figured the motor must have been making high 500's in HP. I figured even if the big drop in compression lost me 100hp I'd still be in the high 400's.

Using an online boost calculator, plugging in 450 for fwhp at 10PSI I am getting 756HP. Subtract 75 to run the blower and that is still 675hp. There will be heat/resistance losses as well but with the intercooler I am thinking it won't be too much. Of course this is all guess work



1967dartgt, I know it doesn't sound good. I'm surprised my machinist mentioned it, he knows his stuff and does all sorts of pro stock, 1500hp street stuff and what not. He said there should be plenty of meat on the heavy speed pro pistons I have in there to take enough down to get the compression we want. I'll have to talk to him a bit more about it, i know it is critical to have enough mass there to resist detonation.

TheOtherDodge, that's what I was hoping to hear! I still don't know if I am going to run 12psi, at least not right away. Judging by what some guys on the boards are doing with turbos, It DOES seem like the motor will take it but I also don't want to have to be tearing it down to replace bearings every year from cap walk. I was thinking the same as you, that 650hp at 12PSI should be doable and maybe enough to go 9's if the car is that light. I hope it is LOL. The blower, brackets, intercooler, sub frame connectors etc.. add some weight.

As for cap walk, my block is half filled, studded and have billet main caps. I haven't been in the motor going on for 3 years so I don't know if I am having any cap walk. The real good thing about my combo is that I shift at 6,000 and cross and 6,000 so I don't have to spin the motor very hard, which saves on parts.

That is good news! What kind of power do you suppose you are making? I'm not sure if a Dakota is really much heavier than my E body?

I am half filling the block and running main studs, but I am using factory caps. I keep debating if I should go crazy and use billet caps but I feel like I have to draw the line somewhere. If I replace the caps and try to push more power through it, now the heads are the weak point and so on. It'll get to the point where I have enough money to buy a resto block sunk into my hunk of junk LA LOL

Guessing based on weight to MPH (3400 lbs with me in it) about 700 hp at the crank on 13 lbs boost. My MPH may be a little low for a turbo setup because I believe my AR (.96) is too small as well as my down pipe (3").