I have a B & M 144 supercharger, so I know I'm going to need low compression but I need some help. I haven't done my own engine rebuild for a bunch of years and need some ideas for selecting the components. Can you guys give me some ideas for new heads, cam, etc.? The goal is a street able 500 hp. The only parts I’m reusing are the new Holley 750 double-pumper, blower, and block (hopefully it’s still good I haven’t had it checked yet). Oh, budget is 3K. Thanks!

 

I've got a fully machined 400 block-4bolt main with studs, it's .040 over, it's has been sonic checked for cylinder wall thickness and checked out @ .200 between cylinders pretty darn thick for a 400. Anyway if you need a block just give me a hoot. To make 500 hp with even that type of blower you have should n't be hard to do. Make sure you keep comp around 8.5:1, 112-114 lobe centerline on the cam, around 220@.050 dur, and any decent (2.02/1.60 about 190-210cc intake port head will give you about 500hp. Good Luck!

 

Thanks for the reply - I'll keep that in mind if this one is shot. :thumbs:


[Modified by Let 'er eat!, 9:49 AM 7/23/2003]

 

With a good flowing set of heads, your blown 400 sbc should have no problem making 500hp :yesnod: . A roller cam will make your goal even easier to reach ;) .

 

That blower is too small for a 400 unless you can live with only 2-3 lbs. boost. I have a Weiand 142 on a 357 c.i. and will only make 5 1/2 lbs. boost with the large 7" drive pulley and a 3" upper pulley...the large 7' pulley will run you an extra $125. You would be much better off with a B&M or Weiand 177 as minimum
You will need to modify your double pumper to "reference" the Holley power-valve to boost or you be running way too lean (read "piston melt-down")when on the throttle. A roller cam is nice but will cost you $1000-plus when all is said and done. You can have any cam Mfg. grind you a flat tappet blower cam and kit for about $500. For $1350 you can get a set of Holley alum heads with ARP bolts, roller timing chain set, hardenend push rods, guide plates and high-rise intake (you can sell the intake since you won't need it with the blower). The kit can be purchased from Jegs or Summit mail order.
You'll need to upgrade your exhaust since your boosting the inflow. Headers and duals as a minimum (I have a used set if interested). I've been the same route and as your thinking of going and will be happy to answer questions as your project proceeds. Deen

 

500hp with a blower? You should have no problem at all reaching 500 without a blower. Just sell your blower and buy a set of good heads.

Deen is absolutely right about that small blower. That blower will barely feed a 400, let alone provide boost.

I would either go with a smaller displacement and theat blower, or simply stay naturally aspirated. A blower is cool to have, but just make sure that it's worth it.

My motor will be back on the dyno in 3 weeks and we have all intentions of making 600hp on pump gas with my 409 sbc.

 

You guys lost me with the boost comments - I'm generating 5-7 lbs now with about 450 HP.

 

500HP with a 400 is very attainable without boost. What size motor do you have now ? Sounds like these blowers are not too efficient (no intercooling)but 5-7lbs of boost should create some good power if the blower is upto the task? (size). Like the other guy said Blowers and turbo's on small blocks should only be an option when you've maxed out the ability to make anymore( streetable?) power NA. It looks cool but it doesn't look too cool when someone is making more power than you NA with the same size motor. Anyway, you should have no problem making 500HP but look into that blower size before you speculate. Good Luck.

 

Boost isn't as simple as it sounds...just because you are generating 5-7 lbs. boost now doesn't mean it is actually getting inside the cylinders. With stock heads you can show a lot of boost but the air is actually stacking-up inside the intake manifold and is restricted by the small valves and inferior port designs, you'll "read" higher boost readings at the intake manifold. With a set of good aftermarket heads and a blower-cam you will show LESS boost but be actually making MORE HP because the air is flowing into the cylinders. This comes directly from the Weiand Blower booklet available from Holley (Holley owns Weiand).
Deen
P.S. Another fact about the small blowers, they are only efficent at "streetable" RPMS (2500-5500 RPM). Above 5500 RPM they are spinning so fast (14000-plus RPM blower speed) they heat the air too much and you LOSE HP.

 

:iagree:

 

Ok, so your saying that my 5-7 lbs that I'm showing now is overstated and when I get some new awesome heads that the reading is going to drop all the way down to 2-3 Lbs? Wow. So, if I still wanted to use the blower I guess I should go ahead and plan on 9.0:1 or even 9.5:1 compression....

see Table 1: (about 1/3 down page)
http://www.holley.com/HiOctn/TechSer...fo/SCTech.html




[Modified by Let 'er eat!, 1:48 PM 7/30/2003]

 

Yes you can do that as long as you never plan on upgrading to a larger blower (more boost).