hi i was planning on building a high performace street motor that runs on pump gas

i havnt got the motor yet but i was wondering if i could get good performace out of 429 4dr merc i dont live by it so i was wondering if it was worth it to even bother looking thats al i know about the car
any advice is appreciated

 

year of the car would be helpful. Basically the answer is yes you can get performance out of about any of the 429s but if it's a 72 it will probably have the D2VE heads that make better door stops then performance or even just passenger car heads. This is due ot being open chamber and very prone to detonation.
Otherwise yes and even with that you can either go with a different factory head or any number of aftermarket like the TFS streets for example that are capable of some real HP.

 

i heard about putting a 460 crank in and that would be an easy way to 500hp
but ist that and the pistons the only diff between the 429 and 460 so how does that make a differance

 

just making it a 460 will not get you 500hp. You are correct on crank and pistons being the only difference.
You can get 500 hp easily with a stroker kit (make it a 521) and make it very streetable. You can also reach that level with a 429/460 but won't be as mild.
All depends on what you want to do, what you want to spend, what you expect out of the engine, and what if any restrictions you have.

 

i would need to bore it over.060 to mak it a 521 right?

also what does stroker mean?

 

Stroker is putting in a crank with a longer stroke thus increasing the cubic inches. for your question you would put in a 4.3" stroke and bore it .030 over to achieve 521cid for example (.030 over on a stoke 3.85 460 crank would achieve 466 cid, and .030 over on a 3.59" 429 would give you 435 approx)

 

The year of the Merc matters - our 69 was pretty strong bone stock and surprised many Chevelles in its day even some 396 cars. But then they got heavier, and as noted the 72 heads were turkeys.

So, what year is it?
Automatic I'd assume?

With that said, Horsepower TV just did a nice piece on a 460 buildup, bone stock 88cc chamber heads (about 9.0cr my guess) and 378hp. With the stock 429cj cam (PAW_SSI's clone is a 218-228 duration) and a little work to the exhaust ports, you'd be over 400hp on regular gas. You might even touch 400hp with a stock bore/stroke 429. If you have a 69-71 Merc and 10.5 compression you'd be well over 400hp as a 429 though it would take at least pump premium and even then might not be happy. But, just a carb/intake/cam/headers would get you at or over 400hp so not much work needed.

Now 500hp is another level, that is either $2500 worth of cylinder heads or a serious rework of some 69-71 iron heads (big valves and porting like crazy) or a bore+stroke kit or both.

 

yes its auto trans, ill tryn get what ear it is

what makes the diferance between the regular 429s and the thunder cj and scj motors

 

First there was a 429-2v, don't see many of them, I've only seen 1 or 2.
Rated at 320hp, actual I think was about 280hp.
I don't know if that was called a Thunderjet or not.


All the base 429-4v's are 429 Thunderjets.
They were rated at 360hp, actual gross about 325hp near as I can calculate from many related dyno tests and my computer.
10.5cr, 600cfm Autolite carb, and a 193-206 duration cam.
Base heads, 206 x 165 valves

The 429cj, Cobra Jet, was rated at 370hp, only 10hp more.
Actually I think it made almost 90hp more, 407hp calculated.
Changes:
11.3cr
CJ heads, intake ports the size of mammoth cave, 224x173 valves
218-228 duration hyd cam
1" taller intake, big ports
Rochester Qjet carb (the only time Ford ever ran this GM carb!)
Better exhaust manifolds, almost as good as the old 406 Fords

The 429scj, Super Cobra Jet, was also rated at 370hp.
I think it made about 408hp calculated, and if the cam was not over-advanced from the factory it would have made almost 420hp.
Not many factory Fords ran 106-107mph thru the mufflers in the quarter.
Changes from the 429cj:
230-230 duration mech cam
780cfm downleg booster Holley
also an oil cooler and 4-bolt mains in all (both) years, and forged pistons.

 

so could i have a reg 429 macined like one or would it be better to just work up from what i got