Best heads for 347 500hp+ applications

[zlat347ci]

Hi all,

Wanting to get some recommendations on what has worked best for people with 347 500hp+ applications?

AFR 185/195/205/220c
Victor Jnr.
Edelbrock E205

cheers

Zlat.

[barnett468]

lots of heads will get you there but i usually use AFR heads

we really need a lot more info and can give you very specific suggestions, however, im guessing that the AFR 195's will suit your needs . You can make more hp with the 205's but imo, those are better suited to a bigger engine like 351 windsor stroked to a 390, 410, 418 etc.

i will also tell you that not all dynos or dyno operators give the same power readings, and a true 500 hp from a 347 is a ridiculous amount of horsepower.

also, unless you want to be revving the crap out of it all the time, you might want to consider an air gap intake.

[boofhead]

Do you want to do this property or do you want guesses?

What you need to do is work out what RPM you want to make 500HP at - it would like need to be around 7000 rpm.

Lets check that it is reasonable;

REQUIRED VE = (9411 x 500 x 0.45) / (347 x 7000)
REQUIRED VE = 87%  which is a reasonable target.

Then you need to work out how much air is needed to feed the engine at that RPM.
Then you need to calculate the Port size and flow needed to feed the engine at that RPM.
Then you need to work out the Cam specs so you can feed the engine at the RPM.
You also need to make sure support gear, intake manifold, headers and exhaust, carbi will not be a restriction to the air flow.

How streetable do you want it.

So from my experience - here is a basic combination based on your question
Goal - 500HP at 7000 RPM
Head:  AFR 205  (But bigger is nice - needs to be matched to the cam)
Cam: around  235 @ 50 / 240 @ 50 HR 600 thou lift around 110 centers + 3 offset
Intake: Vic Snr with 950 mech secondary carbi
Exhaust: 1 7/8 primaries, 30 inch long, 3.5 inch secondaries 20 inch long, twin 3 inch (maybe 2.5 [but need high flow mufflers)
If auto you will need a 4000 stall and good gears 4:11 at least (to make best use or fun from the combination).
 

[boofhead]

Note: I have the parts to build an engine approaching 500HP which includes the Cam, Heads etc though also designed to also be a very streetable engine.
 
         These were for a personal build but  change of circumstances I am willing to sell the parts.
         PM me if interested.

[GLENN 70]

And an after market block  if you are going to rev the crap out of it .

[boofhead]

Nah - very good balance, good machine work, and especially a good tune.

[GLENN 70]

He already has a 347 and must want more go . What heads are on your 347 now ? . You could always put a LS in 

[barnett468]

He already has a 347 and must want more go . You could always put a LS in 

 

[GLENN 70]

  but true 

[barnett468]

but true 

yes, i know . i hate that stupid engine. 

[barnett468]

you also need to decide if you want a hydraulic or solid or flat tappet or roller cam too.

just dont ask if you need to degree it . the last person that did ended up with a thread over 60 pages long . 

[GLENN 70]

Going off topic here but who cares  . A mate of mine has a 6LT  LS with a 780 Holley ,victor jr intake ,up graded cam Hyd still ,good rod bolts eveything else stock  and makes an easy 550 HP . Track proven and made 435 HP @ the wheels behind a auto with a 5000 stall . I hate that stupid engine 

[boofhead]

You know why they make so much HP so easily, ......

The heads are a 256cc head - here we are debating if 205 is to big....Nope no way in fact to small.
Very hard to over size a head on a stroker especially the big 351 based strokers.

[barnett468]

Going off topic here but who cares 

Nobody just as long as you don't bring up some type of citrus fruit party or rugby players . 

 

[barnett468]

You know why they make so much HP so easily, ......

The heads are a 256cc head - here we are debating if 205 is to big....Nope no way in fact to small.
Very hard to over size a head on a stroker especially the big 351 based strokers.

ok, now i'm confused which is no big surprise.

an LS1 cyl head intake runner is 205 cc with 238 in and 203 ex @ .600, so are you referring to a different ls engine?
the "smaller afr 195 is 308 in and 231 ex @ .600

[boofhead]

But the LFL is fine - at least by me.

[barnett468]

But the LFL is fine - at least by me.

Is that the Ladies Football League?

God, I'm soooo confused now. 

[barnett468]

.
Are we going to turn this poor guys question into a 60 page thread too? 

[Fitzy1980]

you also need to decide if you want a hydraulic or solid or flat tappet or roller cam too.

just dont ask if you need to degree it . the last person that did ended up with a thread over 60 pages long . 

 

[barnett468]

 

 

[GLENN 70]

Yes the series 2 LS3 heads are huge . May as well go LSA ,now we are cranking 

[Fitzy1980]

Don't act like you didn't like all that time we spent together... 

[barnett468]

Yes the series 2 LS3 heads are huge . May as well go LSA ,now we are cranking 

I quit...you win . I'm totally lost now.

[GLENN 70]

Best heads for a 347 ,500 HP  are ............

[barnett468]

This poor guy isn't gonna believe a thing we tell him if we keep this up.