Hello, I'm new to the forum, been lurking for a while. I would like to eventually build a low compression 451 and put a McCulloch supercharger. The supercharger is basically a paxton sn60. I don't have the dough to build my 451 right now. I have chance to pick up a low mileage rebuilt 400 short block. It's basically a stock motor that has been cleaned up reringed, new bearings, and gaskets. It's a 77 so it's a low compression motor. I'm thinking about putting the SC on this motor with some 452 heads and playing with it until I can tear it down for a stroker built. Am I nuts? can the cast pistons/crank take a little boost (<8 lbs) what kinda HP could I see if I do this? I would hate to damage the block.

The 400 will take it just fine, however I would be very surprised if that old school supercharger of your would make 8psi on that 400.

Thanks for the reply. Good to hear that it will take a little boost. The SC will be rebuilt by John Erb with a high output impeller so it should kick the boost a little bit.

should be enough for 6. I ran a SN-2000 on a 440 and it hit 6 w/ a modified impeller. Should be enough to get the 400 going

So I picked up the 400 last night. It's actually a .30 motor that was reringed, new bearing, gaskets with a brand new mopar purple 484 camshaft. would this be a good blower cam? it has a lober separation of 108 and I know that 112 is recommended. I also have a comp cams 268h in my 383 with 500 miles on it. I'll be pulling parts of that to put on the 400 so swapping cams is not a big deal. it has a lobe seperation of 110 which seems better. AM I overthinking this. swapping cams is not a big deal but I would rather not waste my time. part of me says it may be win win since the 484 cam may wake up the 383 when I put that in something one day. I guess I'm all over the place.

one more question do I need to upgrade the springs? with either of these cams with a blower? If so what springs are recommended. I'm trying to build this on a budget but don't want to cut corners if it will bite me later.

no use a good cam. That would not be a good boost cam. I used the Summit 465/488 cam.

Is the 268H the old "high energy" series? If it is it will be fine for a beginner set up. I have an ancient crane powermax 260 grind in mine and it gets along alright. That purple shaft would work, but not as well unless the rest of the combo was built around it. Change to whatever springs are recommended with the cam, the stockers likely won't rev as far as the cam will.

Small blower with the 284 cam might bleed off what little boost you can make with that blower. I woulds stick with the 268 that is in it.

The summit cam is a decent choice because of its wide lsa, but of your two cams you have on hand, the mopar 284/484 would NOT be my choice.

Any thoughts on Racer Brown Cams? I spoke with Jim and for around $165 I can get a custom ground cams. I heard nothing but good things about him. That seems like a pretty place to spend a little money to get it right.

Another question what size carb? I have Holley 750 DB on my 383. I realize that I will have to convert to for blow through application, but I'm wondering a 750 is enough.

any of the custom guys can grind you up a good bump stick. Plus they will get you exactly what you need.

Since you have to shell out the $$ to get a new cam, may as well get a blower specific cam. It is not so much the LSA that you should be concerned with, but the valve timing events and total over lap.

If you buy a new cam it makes no sense to buy a off the shelf one. Get a custom one and it will be way better. Doesn't reall cost any more either.

OK so I decided to pull the trigger on a set of 440 source stealth heads. Anyone wanna guess what a stock rebuilt 400 with edelbrock rpm intake, stealth heads, custom ground cam, 8-10 lbs of boost would put out for hp and torque? I know a stock 400 what pretty low on HP but decent for torque. the headers, intake, cam and heads gotta help, so with the boost I'm guessing I should be over 500/500.

Am I off base?

Keep in mind that the better the heads flow, the less boost you'll be able to produce. With that in mind, I don't think 500 hp is out of the question at all. The 750 will flow considerably more when you add more than atmospheric pressure to it. I would consider sending that carb off to Competition Carburetion. http://www.competitioncarburetion.com/index.htm
Tell him your combo and he'll work some magic.

Keep the fuel going and the cast pistons will be ok. Forget to turn on the fuel pump and #3 will burn up..AMHIK.
I picked up a full second w/ 6psi of boost.

That truck is awesome. This is going in a '47 dodge business coupe. Should be about 3600 lbs. This should be a fun torque monster. I'm getting my 727 rebuilt next week. upgrades bands/clutches and a 4 pinion planet.

So quick question about Stealth heads. I have heard that it's a good idea to replace the locks on these heads. Can I swap in Comp cams 7* locks or should I do locks and retainers. Anything else I should check on these besides a smooth gasket surface and the locks?