maybe closer to 8 if I use a thicker head gasket

This is at least the third post I've read this morning where the OP has mentioned thicker head gaskets to lower the static compression ratio. I cannot begin to tell you what a bad idea this is. Higher static compression ratio with a tight squish is doable many times, whereas a slightly lower static compression ratio with no squish might detonate. This thinking comes from John Erb, chief engineer at KB Pistons. Head gasket thickness should be used to set the squish, not the static compression ratio. Piston crown design and combustion chamber volume are used to change the static compression ratio. You do this when you are planning your build, not as an afterthought. :spank:

As far as fuel pump, let's say you are making 600 hp. Fuel is used at the rate of ~1/2 lb of fuel per each horsepower hour at full rpm's, so let's assume 300 lbs of fuel will be used each hour of operation at flat out. Since fuel weighs about 6 lbs per gallon, we can divide 300 by 6 and find that the motor will need 50 gallons per hour at wide open throttle.

The other thing is fuel pressure. You're still using carburetors and carburetors need a maximum of 5 psi to keep the bowl(s) full during operation. More pressure than that can override the needle and seat in the bowl and allow the fuel pump to blow raw fuel into the intake manifold, creating a tuning nightmare for you............................. NO CARBURETOR ON THE PLANET NEEDS MORE THAN 5 PSI.

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Thanks guys, I do in fact have a complete 454, carb to pan, in storage that I could use that I picked up a few years ago. I don't know what's in it, but it would make a great core for a build like this. I thought it might be easier drop one on my 396, but it is probably a better move to just build it up from scratch, and have the extra cubic inches.

Thanks for reminding me of quench.. I remember now that I had to search extra hard for the steel shim .022" gasket I'm currently using now to achieve .040" quench.

Are piston rings a big consideration when using a blower ?

Thanks!

 

Its really not alot of work just dropping the SC on there, Why not just do it with what you have and give it a run, you might be surprised.
I am running a 454 with a 250 SC and a single 750 DP, Runs great, I have brand new blower 750's in the box but not in ANY rush to mount them.

 

Thanks for the input on this guys.. a few more questions on timing-

- In regards to getting the proper timing curve, from the research I've done, it seems like most people do not run vacuum advance on blower motors.. why is that? I know it is best for cruising/economy purposes (which if you have a blower, you probably don't care much about those), but it seems that you need 20+ initial advance for the thing not to blow up at idle, so people seem to lock out timing, or set initial to 20+ and run a boost retard box. Would an alternative be to keep the initial timing less to help with starting, then rely on the vacuum advance to provide the ample initial timing ? Although, does vacuum advance kick in even when turning the starter over (in which case that wouldn't help with hard start issues). Honestly for my application, cruising speed is probably 2500+ rpm so I could probably get away with locking out timing, if I can get the thing to start properly.

To me, it seems there is very little difference between running locked out timing and using a boost retard... the difference being that you will have a little bit less timing at initial and lower RPM's (what is the benefit here ? Easier starts, and you get to run whatever initial timing you want?)

Also can anyone recommend a good aftermarket distributor that is easy to adjust the mechanical advance curve ? Do most of them (MSD/Mallory,etc) have vacuum advance or are they strictly mechanical?

Thanks

 

I run 18 deg initial, no vac, and 34 total, all in at 3000, with a BTM, street driven 8-71 383. I never have kick-back issues and the motor is far from hard starting, it fires on the first hit of the ignition, seems like not even one full roll. You shouldn't have any problem with no vac, like FBird said.

 

Im running 22 initial with 34 total mech. No vac. Excellent 250 with 750 DP stock

 

Thanks guys, don't worry, I'm not buying anything for quite some time - just getting educated at this point... Once I start, I'll keep it simple and buy the proper components as I start tuning.

I didn't realize there is no vacuum when the engine was under load - I thought it was more RPM determinate..so that is definately helpful..

Thanks!

 

Whatever you do pease do not put a blower on the engine as it sits. you said you are at 10:1 or so now. This is not a good starting point. If you do you will be putting that 454 in sooner than you planned

 

Make sure you have a good, consistent source of quality gasoline. I had plenty of guys get towed into the marina with hot boats, hot tempers and hot girls; a lot of times because they got mystery gas at Cooters Bait and Tackle. Full of dirt, water, wrong octane, etc. Make SURE you know what you're putting in the tank. Having to dump say 60 gallons, flush the system, refill with proper gasoline; oh and pay for the tow...makes the bikini girls, and your wallet VERY unhappy LOL