I am wanting to build a 429 for my 55 F-100 pickup that I am currently building. This will be primarily a street cruiser using pump gas (91 octane). I currently have another 429 in it with an Edelbrock Performer and a 750 vacuum secondary Holley on top, Sanderson 1 7/8" primary tube headers a C6 auto, no stall and 3.89 limited slip gearing in a 9" Ford 4 link coil over.

What I am looking at building is a 429 stroked to 520 ci, using a Scat rotating assembly. MSD 8350 distributor and 6AL box for ignition. Reuse the same intake and carb, same headers along with a Comp ***** Thumpa 291 cam kit to include roller rockers. I also have a set of 95cc Aluminum heads and this stroker kit should yield approximately 10-10.2:1 with these heads. I plan on installing a 2500 stall and use the C6 and same gear set up.

I guess my questions are am I going way too big for this truck and use or am I on the right path to have a powerful and fun street machine?
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Questions like this will get different opinions. One will say you can never have too much power just make sure your structure is set solid because stock was not meant for this.....Another will say your truck is so light that a 289 with the right set up burn the tire off and you'll have more then enough fun. I say just do it, sounds like fun.

 

Fully understand. I realized that when I posted. While I am sure it is really more than I need. I also believe there is "No replacement for displacement". I will probably have to change the gearing for sure.

 

Too big? Probably, but isn't that half the fun? It sounds like a blast to me.

 

the weight on the front is fun, but doesn't really matter.

My 460 is not stroked, a .030 over 466, but have roller rockers, largest valves possible, the c9VE high comp heads, my own built long tube headers, and the wrong cam.. (even timing on both intake and exhaust, vs longer on exhaust).
I backed off on the compression to 9.4:1 to keep using street gas.

I get 435HP, 489 lb/ft of torque on the dyno. you should easily be able to pull 500hp.

Mileage will suck, and it'll be tight fit up front.. but what the heck.

Sam

 

Thanks guys!!

I talked to a life long friend tonight who builds these for a living and he concluded everyone says "I want to keep it streetable". His addage, "If I can start it and drive it on the street it is streetable".

Yea, I am sure mileage will suck, but since I already have one tucked in this thing I know what I am up against literally. I will probably have to put big jets in the carb or move to an 850 to feed this beast if I use the upper end of the horsepower spectrum.

Thanks again,
Pat

 

Personally, I wouldn't be too quick to dump your 750 Holley. That 3310 vac secondary is a very versatile carb and is great for the street. You're not going to want to twist that stroker over 5500-6000 on a regular basis anyway if you want it to last. That's a lot of mass to swing. Let the big cubes do their job at the lower rev range, utilize the torque instead of the peak hp, and take advantage of the better throttle response the smaller carb will give you. You'll definitely want to tune it to match your combo, but I'll bet it'll work great for what you're going to do with it. If your goal was to make an all out drag truck instead of a street machine, that might be different. That's my 2c.

 

Wayne, I tend to agree with your carb comment. I figure put a secondary metering block on it making it basically a 770 and jet it up that should be more than enough carb for my tooling around up to 4500 or so between gears on occasion.

Thanks
Pat

 

Just doing a quick calculation, if you have 520ci and spin it at 4500, your engine would be wanting 677 cfm of airflow if...and that's a big if...you had 100% volumetric efficiency....nobody with a normally aspirated engine has 100% volumetric efficiency. The 750 should be fine as-is.

That being said, a carburetor basically measures airflow and adds fuel at some rate. The rate is based on the jet size and the float level. If you run at a higher rpm, more air flows through the venturis and more fuel is added to the air stream. It is enough fuel to maintain the same fuel/air ratio. If you increase the displacement of your engine, the carb doesn't care....it only knows how much air is flowing through it. What I'm saying is that if your jets currently add enough fuel, they'll also add enough fuel for the bigger engine.

When you finish your engine build, I'd put the known good carb on the engine for break-on, and keep doing spark plug readings to see if the mixture is correct. Some engines like a little more fuel than others, which is why the jetting kits have only small variations for tuning.

Dan

 

Bringing an old thread back to life. I have this same motor (520 ci) in a 79 Bronco. it is a full roller motor, with trick flow heads and an 850 dominator. My headers are 1 3/4" primaries. Is this too small, would it be restrictive.

I have not been able to find a set of headers with a 1 7/8" primary for my application. The Bronco will be going in for new exhaust due to the original owner installing to small a pipe and mufflers, from headers out (2 1/4"). I will be going to 3" through 40 series flowmasters.

Any thoughts ?

 

My thought is, no offense,but I think you are in the wrong forum. We are primarily interested in restoring and modifying 48 -56 F100's and larger trucks, not in building HP engines or other vehicles. I think there are other forums on this site where you might get better answers.

 

I understand the forum, but this particular thread was based on the same engine that i have. I was hoping for some real world input.

Not trying to disrespect the area, but the original post was based on the size of the engine.

 

Do it.

Then your truck will be able to sound like and do what this one does.