Thread: Considering putting a blower on my 406 - have a few questions!

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Well i have a 400 .060 over right now. cast crank, re-conditioned 5.7 rods with arp bolts, speed pro hyperutectic pistons, vortec iron heads with 1.94 1.50's. runnin a lunati hyrd cam. All balanced. Alright so thats what im working with.
I'm considering a blower, but im wondering how well it will bolt up to the vortecs, whether there is a special blower for the bolt pattern. Also, with my combo, 64 cc heads, im at 10:1 c/r and i need to know how much a blower is going to increase my c/r, if any. As I would rather run it on pump gas
My combo should produce 425 hp and 523 lb tq. but with a blower id probably be pushing 550 hp with maybe 600 lb tq. you guys think my gm block would handle that much? with the rods, and crank? Is it worth it? this engine will be spinning 5500.
Any input is greatly appreciated.
Thanks, Cory

You would have to change alot of stuff for a blower. With a 60 over 400 that can run hot sometimes plus a blower that runs hot---I wouldnt.

Thats what i'm thinking as well, its a pretty spendy investment as well. thanks for the input

Thanks Denny, that helps a lot. Do you think It would have cooling problems? Being .060 over inall. I suspose Id wanna run a forged crank, rods, and pistons with the blower.

Thanks for the good info, it helps a lot.

Too much compression. Max for a blower on the street is about 8.5:1. Should have forged crank and rods, too.

Keep the blower small (6-71 maybe). Definitely a cam change designed for your application. Head swap for breathing purposes (a bit more exhaust to evacuate). Siamesed bores on the 400 block will be a strength for you and if you already have adequate cooling, there should be no problems. Remember the camshaft centerlines and the overlap for a blown engine is dramatically different from naturaul aspiration. Crankshafts were known for breaking into two peices with the cast OEM 400 setup, be weary of what you wanna do until you know for sure which it is. And no matter which heads you run, please match the steam holes in the head for a stock block setup. Hope this helps.

Originally Posted by facemelter

Well i have a 400 .060 over right now. cast crank, re-conditioned 5.7 rods with arp bolts, speed pro hyperutectic pistons, vortec iron heads with 1.94 1.50's. runnin a lunati hyrd cam. All balanced. Alright so thats what im working with.
I'm considering a blower, but im wondering how well it will bolt up to the vortecs, whether there is a special blower for the bolt pattern. Also, with my combo, 64 cc heads, im at 10:1 c/r and i need to know how much a blower is going to increase my c/r, if any. As I would rather run it on pump gas
My combo should produce 425 hp and 523 lb tq. but with a blower id probably be pushing 550 hp with maybe 600 lb tq. you guys think my gm block would handle that much? with the rods, and crank? Is it worth it? this engine will be spinning 5500.
Any input is greatly appreciated.
Thanks, Cory

A .060 over 400 and you want to put a blower on it?
First your lower end won't take it and second you would not have much of a chance to hold a head gasket on the engine.
Then there is the heat issue of the 400.

Originally Posted by erik erikson

A .060 over 400 and you want to put a blower on it?
First your lower end won't take it and second you would not have much of a chance to hold a head gasket on the engine.
Then there is the heat issue of the 400.

No i didnt say I for sure want to. The thought went through my mind, and I was considering. I was already pretty sure it wouldnt be a very wise decision. But I wanted input is all I wont be running a blower, I'd have to change to a forged crank, rods, and pistons.

.....this really isn't related to your question but a .060 over 400 is 413 cubic inches.... Bill

Originally Posted by billlsbird

.....this really isn't related to your question but a .060 over 400 is 413 cubic inches.... Bill

Thanks Bill, I'm quite aware of that

Originally Posted by nitrowarrior

Keep the blower small (6-71 maybe). Definitely a cam change designed for your application. Head swap for breathing purposes (a bit more exhaust to evacuate). Siamesed bores on the 400 block will be a strength for you and if you already have adequate cooling, there should be no problems. Remember the camshaft centerlines and the overlap for a blown engine is dramatically different from naturaul aspiration. Crankshafts were known for breaking into two peices with the cast OEM 400 setup, be weary of what you wanna do until you know for sure which it is. And no matter which heads you run, please match the steam holes in the head for a stock block setup. Hope this helps.

yep I sure do have the steam holes drilled. I have iron vortecs for the engine. I dont think I would trust running the blower on the cast crank I have, In which my rotating assembly is now balanced, it would be a nice waste of my 175 if I decided to get another crank, rods, and pistons to match.

Obviously at 10:1 you are not going to tolerate very much boost. An alternative might be a centrifugal charger running about 4-6 psi maximum. Blow through a proper carb and you will get a reasonable cooling effect that might allow the 4-6 psi boost. If you also use an intercooler then the boosted charge will be nice and cool and the higher CR will less likely lead to problems. The bottom end is another story. They put blow through centrifugals on street cars with relatively high CR's commonly.

I'm considering one for my 502 with 9.6:1 CR. But I am also considering putting some larger heads on it to knock the CR down to 9:1 first.

Kitz