New Motor

427sharpe · #1 (**permalink**) 05-17-2002, 10:07 AM

Just as a curiosity, I have purchased a slightly used BOSS 429. After careful consideration, many measurements and some pad and pencil work, I have decided to stroke it (crank and overbore) and install it in my Cobra. The 535 I run now has been wonderful, and it will find a home in the 56 Ford pick up I am working on now. I have decided to max the motor, cube wise, as far as I can go without trashing the block. I think 550 cubes is about right! Have any of you guys tried doing this on a BOSS? I have talked with the Holman-Moody, and their shop is going to do the machine work and sell me the bits and pieces to finish her up. I have given them a 'want list', in that I want a true street motor that will live and be enjoyable (already unique, I think!) and they tell me 650 hp and 600 lb ft! Lee Holman says he thinks he has a one off Weber set up for it! I will take some pics and post them as it progresses, especially the install when the motor goes in! Let the envy begin!

SFfiredog · #2 (**permalink**) 05-17-2002, 01:34 PM

I have built some Boss 429 stroker motors, mostly for boats. Boss 429 blocks are usually thick enough in the bore to go to 4.5" I did have one "T" motor that would only go 4.44" safely though.
If you have the block sonic checked and it checks good with at least .150" to .200" cylinder wall thickness at 4.5" you could go 4.5 bore and 4.5 stroke and get 572 ci. At 4.44 bore with a 4.5" stroke you would get 557 ci. Cast steel crankshafts are readily available or if you have the money you can go with a custom forging or billet ($$$$$$$!). There are many variables and unique procedures that need to be followed when building a Boss.
Fell free to e-mail me privatley and I can help you with your combo. The weber manifold is way cool but the 48 IDA carbs that are available (no more 58mm) have no chance of feeding enough fuel for this motor.
I would get the manifold and convert it to 8 stack electronic fuel injection.
Good luck with your project.
Mike Braun

69boss429 · #3 (**permalink**) 12-13-2004, 02:21 PM

I recently found this forum and wondered if anyone had a BOSS 429 in a Cobra. Did you get yours built? I have a 1969 BOSS 429 that I warmed up a little. Although it is only a .05 overbore,with a stock crank it dynoed at 600 hp with a rollar cam, dual 715 Holleys,MSD ignition, and custom headers.I am considering building a Cobra using a C& C performance all aluminum BOSS 429.I would love to hear about your Cobra. Email me at dteter@ptdprolog.net thanks

wboss429 · #4 (**permalink**) 12-20-2004, 09:31 PM

IVE DONE A FEW BOSS NINES ( YOU COULD SAY).U DONT NEED TO GO TO THE EXXXXXXXTREAM FOR 650 HP A 10.7 TO ONE 514CI ,80 OVER WILL RUN COOLER,AND MAKE THE POWER U WANT EASY,WE HAVE THE LAST ONE IN A EVERY DAY DRIVER A 1995 F350 4X4, IT MAKES OVER 600 ON A BAD DAY, ONE OTHER 514 MADE 849 HP AT 6600 RPM, (IT HAD MORE COMP)