I placed this also in the C3 section, but thought this might also be a good place because of the crossing of different generations.

Finally put all the finishing touches on top end of the blower in regards to making all my bracketry, spacer, plates for regulators, etc. In the process of that I pulled the intake and am currently trying to figure out what possible vacuum ports I am going to have to tap into to make everything work. Here basically are my 3 questions.

1. Power Brake Booster - I'm using the basic vacuum assist setup. The vacuum for this Holley recommended getting from the carb adapter plate (one of the two ports in the back of the adapter plate).

2. Signal for Power Valves - I'm using Holley's blower carbs that are set up for external power valve reference. I'm assuming :eek: that I should be referencing vacuum off the intake itself and will have to tap into it somewhere (will probably drill/tap hole into the flat area in front of the distributor). Opinion?

3. Transmission - I'm using a modified Turbo 350, after a few discussions the intermediate sprag is the weak link on these. Transmission has been rebuilt with a aftermarket sprag assembly along with some other goodies that should be more then enough to handle the motor. I have a choice of going with full manual valve body or sticking with the just put it in drive and let it go. BDS has a pressure diversion valve http://www.blowerdriveservice.com/carb_valve.html so the transmission receives the proper signal and shifts correctly. Talking with them (although when I said I didn't have their brand intake they kinda cringed) this also has to be ported to the intake. Has anyone ever dealt with anything like this?

Thanks in advance,
Keith




[Modified by 70PurpleLS7, 10:21 AM 5/21/2002]

 

#2 yes you must tap into the intake manifold for a vacuum reference but i tap into the manifold blow off plate because the line will see the vacuum to boost change quickly. :chevy

 

Clem,

BDS had mentioned about tapping into my blow off plate, what type of system are you using. Weiand's blow off plate doesn't allow much room to do any tapping. Have any pictures?

If push comes to shove, I'll tap into the intake in the area in front of the distributor.

 

i build for other people and mostly blower boat engine so i have no pictures. as long as you do not tap into a single intake runner you should be ok because there is a positive/ negative pluse that will cause you trouble. :chevy


[Modified by clem zahrobsky, 2:34 PM 5/21/2002]

 

Thanks for the heads up - I'll look this evening to see how much room I have back there.

 

Clem - Blower boat engines ... now you've hit on my other interest, as I have a Formula 402 with twin N/A BB's that I use to keep down the world supply of excess gasoline. I've been toying with the blower idea for a couple years but am still a little too scared I'd just end up trashing more motors (I had one go with a broken crank a couple years ago).

Would love to hear more about your boat engine work. e-mail me if you like (greg.page@nrl.navy.mil).

-Greg

 

i am now retired and no longer build engines but i have built 454 and 510 blown boat engines. you must have 8.5 compression ratio with good forged pistons and heads that all the chambers are smooth and equal in CCs so you have no pre ignition. we run 6.5/7 # of boost on 93 octane pump gas. you must also run a water to air intercooler to prevent problems. a good hyd roller cam and exhaust system will make over 750 HP with the 510s. :chevy


[Modified by clem zahrobsky, 11:59 PM 5/22/2002]

 

Clem-

Yes, the problem with "adding" blowers to my motors is the compression. They have all the heavy duty internals and forged parts, but the "wrong" ones ... they currently are at 9.8:1 compression.

Chief said I could run 3 lbs boost and get about 550HP. That's only about a 50-75HP boost, which in a (big and heavy) boat isn't enough speed difference to really make it worth while. I've thought about swaping to some better heads, but again 50-75 HP isn't enough to be really significant (maybe 5 mph).

It's much too expensive to have the engines pulled and reinstalled (about $4k last time around, but I did have them do a little hull work too which was probably a grand of it) unless I could get some major increases ... your 750 HP would be nice but probably too much for my drives, which means more money which ... :crazy:

Guess that's why I've left it as it is so far :)

Thanks - Greg

 

with 2 454s in a 32' scarab we had to water cool the gear heads on the outdrives. this boat would break 100 mph. one guy around here has a tunnel hull with 2 572 cu in blower motors and has radared at 127 mph on the river. :chevy :D :D