Lee_in_KC
Active Member
I thought I would start a new thread to respond to Ron's questions so it wouldn't be buried in my paint thread.rcruse said:
Regarding my motor, the first thing I did is research blower motors in depth. The best resource I found was this book... [ame="[url]http://www.amazon.com/Street-Supercharging-Install-Blowers-S/dp/1884089291/ref=sr_1_1?ie=UTF8&s=books&qid=1238854466&sr=1-1[/url]"]Amazon.com: Street Supercharging: DIY Guide to Street Supercharging, How to Install and Tune Blowers (S-A Design): Pat Ganahl: Books[/ame]. I also read several other books on building performance small block Chevies.
My plan was to have a good, solid street motor... not necessarily bullet-proof, but strong in the low to mid range. I wanted to build the whole motor myself from a bare block up, but I just didn't have the tools or experience to have confidence I would have a good foundation for a blower, so I found a reputable motor builder and ordered a short block. I got a purpose-built, race-prepped short block from Scott Sehr (Sehr Performance Machine Engine Rebuilding Specialists)... .030-over, four-bolt 1979 truck 350 small block, cleaned and magnafluxed, checked for core shift, align-honed (crank and cam) parallel-decked, torque-plate honed, GMPP cast crank and rods, Sealed Power "blower" pistons. My one regret is that I didn't have Scott do a 383... it was only $200 more. 383s are torque monsters and just sound meaner for some reason. Maybe I'll build up a new 383 short block next winter.
Scott had Comp Cams do a special grind hydraulic roller "blower" cam... I wanted low-end torque and as lumpy an idle as I could get and keep it streetable. Blowers tend to smooth out lumpy cams. Unfortunately, Scott misplaced the cam card, so I don't have the exact specs on the cam. I used a degree wheel kit to try to reverse engineer the cam and came up with an .050 duration of 231 intake, 236 exhaust, .478 lift (at the valve), 109 LSA (more overlap than recommended for a blower because you end up blowing some of the charge out the exhaust, but that's where the lumpy idle comes from).
Top end is Dart Iron Eagle S/S 76cc heads (built-up by Dart), Comp roller rockers (over-kill but they look cool), Comp hydraulic roller lifters.I added a complete 6-71 blower kit from Blower Drive Service (good recommendations here... Blower Drive Service: We Deliver Horse Power! - Blower Drive Systems, Blower Kits, Blower Cams, Custom Carb Service ). It is set up 1:1 for about 6# of boost at 5,000 rpm. I'm using an MSD 6AL ignition box rev-limited to 5600. Carbs are Edelbrock 600 cfm 1405s re-jetted for the blower per Edel's recommendations. The carbs are dirt simple to tune and perform well, although they are sensitive to fuel pressure (e.i. too much!). Timing is through an MSD pro billet distributor recurved for mechanical advance of 1200-2800, 18* initial, 34* all in.
My motor has run strong and reliable from day one. I have not had the farting, snorting, back-firing issues that some complain about. I get about 6 mpg in town (too many fast-leaves from stop lights
) and about 9 mpg highway. I know I am running pretty rich, but I want to stay well away from detonation (blower motor's worst enemy!). I hope to put the T on a chassis dyno when I get the car put back together and get a good tune on the fuel/air mix.Blower belt... from what I've learned, belts can be an issue if you are running high boost and/or are running the belt tight to get the blower whine. I had my belt pretty tight to start with, and I was seeing a lot of black powder building up on my polished water pump. I loosened the belt to BDS's recommendation and I'm seeing less powder build-up. Of course, it doesn't whine as much, either.
Supposedly (I haven't tried it) the motor will run without the belt.Heat in the motor has not been an issue for me. I'm running an all-aluminum 2-pass radiator with a Spal 2600 cfm electric fan. I have never seen anything over 210* even on a 90*+ day in stop and go traffic.
I appreciate the compliments on my T. It has turned out exactly as I envisioned it when I first decided to build it. It is built from a Spirit Stage III kit, with some modifications. The stock Spirit chassis sits higher in the front than I wanted, so I met with BC and Jeremy to re-engineer the front end. They raised the spring perch 3" and the steering box mount 1.5" for more clearance. We had to go with the front-mounted tie-rod set-up because of the lowered front frame. The stance is exactly how I want it now. The Spirit folks are great people, very accommodating and helpful. I highly recommend them.
Hope I covered everything for you. Feel free to ask more questions. As you can see, I don't mind talking about my hot rod!
