Quote:
Originally Posted by Bored&Stroked
What all of us should have asked is what is your definition of a 'mild blown street motor' - and what car, what trans, what gearing, etc? What are the specs you're thinking of for the engine?
Bore / Stroke / Cubic Inches
Porting and Relieving - none, or to what level
Valves - sizes
Heads / Chambers / Compression Ratio
Ignition
Blower / Overdrive / Boost
Fuel system - type, number of carbs (if carbs), approximate CFM
Flywheel / Clutch
Tranmission, Gearing
What characteristics are you looking for in the engine? How will you be driving it and what are your overall goals?
I think myself and others 'shot the gun a bit' - we were off the diving board and into the pool without knowing much. My bad! 
B&S |
This motor will be going into my 1935 5 window coupe (avatar).
I'm in the early stages of this, so there's a lot I can't answer for sure.
I've done a lot of reading and researching, but have no experience with a Flathead build. I'm very good at understanding what I'm reading and I'll have no problem bringing it to the workbench. Machining will be left to a competent shop.
Right now, I know for sure that I don't want to build an all out race engine as this car will be used for cruising. I can't see spending a ton of money on a motor that's driven to local cruise nights, etc.
Here's what I have in mind, & please everyone give me your opinions and experiences, every bit will help me decide which way to go.
Again I'm not an experienced engine builder, but very handy.
Bore will be 3 5/16
I have a 4" Merc crank that will be used with stock conrods and Ross forged 3-ring pistons. Crank & rods will be magnafluxed, shot peened, etc. Heavy duty center main cap? Not sure on an align bore yet. Suggestions anyone??
276 ci.
Complete engine balancing.
From what I read about relieving, it's not needed for a street motor. Porting & blending to clean things up will be done.
1.6" Manley street flow valves. Isky single 185G springs
L100-B cam Thanks Kiwinus!
Ignition will be a Mallory Unilite with mechanical advance, set up by Bubba, of course, with an MSD Boost Timing Master
I would like to use iron heads because I like the way stock heads look. I know about the detonation concerns, but from what I'm reading iron heads can be used without problems.
My CR will be determined by chamber size which I don't know right now, but I'm looking to stay on the low side, 7.2:1 and up so I can safely and effectively keep the boost a little higher (6 psi).
The blower is a Camden 9". I don't know if different sized pulley's are available to change drive ratio
I did this calculation based on Joe Abbin's book to get the drive ratio.
14.7 + 5 x 276 = 5437.2 then divide by
14.7 x 1.7 x 144 = 3598.56
Drive ratio is 1.51 for 5 psi & 1.58 for 6 psi.
I measured my top and bottom pulleys and came up with this.
Bottom 7.75" x 3.14 = 24.335
Top 5" x 3.14 = 15.7
24.355 divided by 15.7 = 1.55 This would close to my drive ratio, correct??
The blower came with a Holley 600 cfm carb which I'll be using
I don't know what what size clutch I'll be running probably a 10" with a steel flywheel.
Trans is a 1993 T5 world class. 1st gear is 4.03, 2.37, 1.49, 1.00 & 5th gear is .76
Rear is a Ford 9" with a 3.55 posi.
I'm looking for a reliable street engine that will be driven to local car shows and taking my kids for cruises for a couple of hours here and there.
No drag strip. I don't care for top end speed just a good running motor that looks really cool when the hood is open!
Please remember, I'm not an experienced builder & I'm always open to all suggestions!
My top reads are "Nostalgia" by Ol' Ron, "Flathead Facts" by JWL and "Flathead For V-8" by Joe Abbin
Thank you,
Joe