How much hp is ported 4v heads good for?


"D"

 

well most people dont or wont port 4v heads. its pretty easy to mess up the port job. having said that, shazam is getting 800 out of his boss 302 heads, almost the same as 4v heads.

 

Actully I have the Boss 302 heads on my 426 4.100 Stroker 400 putting out 620 H.p. and 592 # T.q.

I have Boss 351C 4V heads with Highport Plates on my 435 4.200 Stroke 400 putting out 799 H.p. at 667# T.q.

The Boss 351C heads where ported at Price Motorsports out of Indiana Call them at 1-812-546-4220 talk to Mary and see if they still do porting I know Mary was hanging it up a few years back , Maybe they have a new head porter in shop by now .

 

Hey shazam, I too have a set of boss 302 heads on my windsor. I didn't stroke mine though. I am using a set of price motor sport spacers with a boss 302 intake. I didn't port my heads though I didn't think that porting those huge ports would make a difference. I have been looking at building another short block as a stroker. How do you find it works with those heads and with the stroked 351 can you still get the rpm out of it??? also at what rpm does your peak horsepower reach? Kinda cool to find someone else that has done the same similar motor. Bob

 

Well Blie: First off I have a Stroked 400 Not a 351w, I find these heads are pretty good for being 30 yrs, old And I've only found a few Aluminum Heads that can out flow these Cast heads.I have the Highport plates on my 435 and I'd say there good for 50 to 75 horses over just porting the 4V heads.
Where does my motor make it's most power Peak Horses power is at 6500 Rpm's with peak torque at 5500 Rpm's but it will spin over 8000 Rpm's without much coaxing.....

 

Shazam,
Are there any advantages with a 400 in any stroked cube variance over a 460?
I know the big bore helps the 460 by reducing the piston speed.
Also, better aftermarket support.400/351C heads are crap high performance wise unless you spend $$$ correcting the runners or raising and recutting exhaust ports or use plates.
But, like I said so many times it's just so damn heavy. Crank is 72 lbs alone compared to 60 lb 400 crank. Block is at least 240 lbs and 400 shy over 210. The long stroke helps the 400 but it faces a detrimental 58 cube difference. The 460 is a monster when properly built and can easily produce 400's highest hp/torque before 5000 rpm easily.




"D"

 

I used to think the 460 was 150 lbs heavier than the 400, but some recent detailed info on the 351C and the 429 here has somewhat changed my mind.
http://home.earthlink.net/~tcrocker/...WeightsV1.html

Draw your own conclusions.

 

Well hellraiser:
Your right Mod for Mod the 460 will out produce the 400 everytime. You just can't replace displacement. A .040 over 460 will make more h.p. then a .040 over 400. But one has to ask is it worth it with the extra weight the 460 has.
Does the couple extra h.p. the 460 makes over the 400 outway the extra weight it has to push around .
OK I play some on my Desk Top Dyno 2000 took a 460 and a 400 made them both .040 over and Stroked them .200
here's the numbers.

460 675 Hp. @ 6000 Rpm's 667 Tq. @ 4500 Rpm's

400 667 Hp. @ 6500 Rpm's 617 Tq. @ 5000 Rpm's

 

Not that im saying one is better than the other. The cost of building each, is probably way better for the 460. But it is interesting to know that the good old "cleveland" heads really do work. It is my guess tha the heads is why its that close. 8hp and 500rpm.

 

I'll let you in on a little secret the 351c heads where designed from the 429 - 460 heads. Same size valves, same angle design, and Same rocker geometry.

 

Shazam,
the 400 is actually 402 CI. 460-402=58 CI difference. If you multiply the 58 CI difference times an easy attainable 1.3 hp per cubic inch, that's 75.4 hp. 75 hp of course stretched out through the rpms for the 460. I beg to differ at the calculations.Probably, a little more advantage with the 460. Especially with the exhaust strangled heads of the 335 series. Even with major porting couldn't outflow a DOVE head or any of the various aluminum heads available.I don't think there's enough cfm with any of those heads.I guess because of the big cubic inch difference a radical mod for a 400 is mild to a 460 and is why the comparison is so close.

There's about a 75-80 lb weight difference stock. However, due to the more affordable aluminum heads for the 460, the weight can drop as low as 585. An iron headed 400 with aluminum intake and so forth is what, 550 lbs? Not a whole lot of difference.
I'm not an advocate for the 460. I'm just looking for some awesome advantages to really make me want to build the 400 over the 460. I have complete parts for both.The 460 doesn't require any fabrication work.The 400 will be more $$$ to get the same power.