I have a 73 400 that is currently rebuilt .030 over with the usual bolt ons and I want mroe power. I am utilizing the stock valves with a 3-angle valve job and the heads are gasket matched. The heads have the bump on the exhaust floor and am wondering if anyone has had these heads ported to perform well and where were they done and the cost.
I want 450 horsepower, but I realize I will probably only get 425 max. I would like torque to be at least as high as the power.
If anyone has any suggestions, please feel free to type em up.
thanks

 

For a start you could fit the larger 4v cleveland valves in place of the stock 400 ones.

 

I'm afraid the 4v head would kill your torque at low rpm's. The bumps can be ground out and a little bowl work and port matching go a long way on a street motor. Headers are a good thing!

 

I had a motor in my 77' F250 (had being key) that was turning 425hp and right at 500#'. Didnt seem like we did that much to it, my Dad was a dirt track stock car driver and jack of all trades (Professional Mine Safety Engineer).

We started with my 400, bored 30 over just to clean the holes. Flat top TRW (back when they made 400 pistons, 1990ish). We had all our rotating parts balanced (ie pistons, rods....). Did all the normal stuff, performer 400 intake, competition cam?? 292 w/ 510 lift...(a little radical, didnt hit good power till 3000 rpm - after all- the 400 was never ment to be a drag motor).

My Dad has some of the equipment to do this in his garage (boring bar, valve grinder, seat grinder) and with his race connections had the other stuff done for swap. He took the die grinder to the heads and must have gotten luck with the shade tree port and polish...or is just better at it than I thought.

The only carb we had was off his race car (428 pontiac) and was a 780? (he swares it was, I cannot find a 780) holley double with mech seconaries.

I had dual exhaust, but no headers...could not find headers to fit the dana 60 front end. They used to put a footnote saying it wouldnt fit the 77 1/2-79 with the dana 60? Does anyone know if the new headers fit? the footnote is gone now???

Heads were shaved .015 (I warped them, oops, was a dumb kid). No other major alterations that I can think of, maybe all the small stuff ads up. ie: sandwiched mesh (screen) on intake gasket (help atomize the fuel/air).....Who knows, but thats what she was truning.

 

>I had dual exhaust, but no headers...could not find headers
>to fit the dana 60 front end. They used to put a footnote
>saying it wouldnt fit the 77 1/2-79 with the dana 60? Does
>anyone know if the new headers fit? the footnote is gone
>now???

I don't know about a footnote but I have a '78 with a front 60 and those cheap $79.50 summit headers. No problems.

 

that is quite a bit of duration. Too much for my setup:4300 pound car, C6, and an open diff with the stock 3.00 gears.
But, thanks for the information. Do you remember when they hp and torque peaked?

 

No, sorry I cant remember. I do remember that it built pretty nice, then hit a hard swing up around 3000 with peak hp around 3600-4000?? Course I could be waaaayyyyy off. I would like to recreate that motor some day, wish I had kept more documentation on it.

The truck had plenty of power, its a 6000lb beast with detroit lockers in the rear and posi in the front...Does have 4.10 but with 33" tires...thats about a 3.73ish to the ground. It would lay about 4-5' of rubber before it started to wheel hop on all 4 tires...(course that cost me a couple drive lines and some gears, took a while to figure out what caused those major falures...)

I do remember that pulling heavy loads up hill was hard for it unless you had it reved' to 3000 already. (8-10% grade). Course this is in Wyoming (6500').

The only problem was that HUGE carb...It would caugh pretty hard if you just tried to stand on it...had to roll into it (1100rpm or so) or rev a bit and dump the clutch (but I knew that was hard on it, so I tried not to do that often)

 

if you search some of the old threads, you will see my build. it will make the power, and its not even a radical setup.

 

>I don't know about a footnote but I have a '78 with a front
>60 and those cheap $79.50 summit headers. No problems.

They arent fenderwell headers are they? (exit the engine compartment and run down the outside of the frame)

 

[updated:LAST EDITED ON 09-Aug-02 AT 11:30 AM (EST)]>if you search some of the old threads, you will see my
>build. it will make the power, and its not even a radical
>setup.


any tips for searching?
i did a search in "AND" mode just in the 335 forum, looking for "gt40man my 400 build heads intake cam headers pistons" and got 33 results that had ALL of those words in them! none of the threads that were started by you (only 4 in 22 pages!) had it in there. did you post it as a new topic, or a reply to one somebody else started? do you remember how long ago it was, and any key words to search for that would be in that post, and NOT in so many others?
thanks!

 

I'm running the smallest Crane hydralic roller cam (out of 5) and desk top dyno says I make 435hp but the kicker is the torque. 510# from 2,000to 4,000. Thats what it feels like too.

However, the roller wasn't easy to set up. Had a machine shop do it and some of the Crane parts seemed to be made for th 4v head not the 2v. Of course it's not the cheapest solution but a roller gives you the best of both worlds.

 

i'm planning to make mine a roller too - not sure yet if it'll be solid or hyd. - but it looks like either way, the lifters are a lot taller than the flat ones. one way i've heard about doing it is to use a smaller base circle cam with regular late-model lifters. the other way is to use a regular cam with special lifters...


how did you do yours? do you know what sort of extra machine work had to be done? are there off-the-shelf cams with smaller base circles made for this purpose?

also, i've heard of lifter bores on one side being reamed out & bronze bushed for oil control purposes - i'm thinking maybe they could all be reamed & steel bushed, with taller bushings to extend the height of the bores for the taller lifters. any idea if this would work?

(maybe do the oil thing too, if the latest thinking on oiling hasn't rejected that method...)

also, i'm wondering about the rev limit of the stock hyd. roller lifters vs. the aftermarket "stock replacement" ones, vs. the aftermarket "roller conversion" ones...

 

ok here it is


400 block
3514v heads
2.19/1.71 valves
dynagear flat tops pistons
wieand xcellerator intake
demon 750 carb
crower 15174 cam @.050 227/233 .550/.547 lift
rhodes lifters
2 inch headers


495hp 504 torque

im thinking of dumping the vavles for 2.25 and 1.75

 

GT40man

what kind of gas milage does that motor get. i got a 7000# truck with a D60 in front and D70 in the rear with 410's and i like the hp and 500# you got out of it. also where did you get the flat top pistons

Paul

 

http://www.dynagear.com/html/products.htm

What was your final compression?

I don't think I would run a bigger intake valve but I would like to know if there is enough room to fit a 2.25/1.75". Won't you have to notch the cylinder for the 2.19"?