What Heads ?

[ozzymaxwedge]

Hi all,

Looking for a little power, (always) for our big block.
Currently 440/528 4.375 Molnar crank, Eagle rods, kb 12.6-1, maxed out SR heads 360 cfm, Huges rockers, .700 net lift solid roller, Crower lifters, Indy tunnel , twin APD 950 carbs.
3650lb but dropping 200lb out, has gone 9.69@139

Would there be some good gains going to 440-1 ? With what cnc and valve ? Or maybe a better head ?

Thanks for your ideas

 

[33 IMP]

My choice in your spot would be ported B1. (I understand as cast dint live up to the hype).
I think the 572-13 indy need a 4.5 bore.
I think the -1s would also be an improvement, the question is, enough to be worth the swap? I don't know.

 

[ozzymaxwedge]

My choice in your spot would be ported B1. (I understand as cast dint live up to the hype).
I think the 572-13 indy need a 4.5 bore.
I think the -1s would also be an improvement, the question is, enough to be worth the swap? I don't know.

think I’ll give the B1 a miss, yes 572-13 is 4.5 I think .
If it’s 440-1 do I go 325 cfm or 345 ?
Do I go bigger valve (2.25) or not for my combo ?

 

[33 IMP]

If you want more than what you've got, get more than what you've got. 345s with big valves. Give the new heads a fair shot to be better than what you have
(345 is NOT real big for 528". 396 chevy had 320 in 1965)

 

[PRHeads]

I guess you’d need to ask yourself………how much more power would the new heads have to make to justify their cost?

I have ported SR’s that flow in the 360 range.
Cnc345’s with a decent valve job(2.25” valve) and some minor blending are in the 380 range on my bench.

572-13’s will require pistons with a different valve pocket location and angle.

They have larger runners & bigger valves than -1’s, and flow better at the higher lifts………but give up a fair amount of flow to the 345’s in the lower/mid-lifts.

 

[ozzymaxwedge]

I guess you’d need to ask yourself………how much more power would the new heads have to make to justify their cost?

I have ported SR’s that flow in the 360 range.
Cnc345’s with a decent valve job(2.25” valve) and some minor blending are in the 380 range on my bench.

Thanks for the replies,
So if the SR’s are 360 and the 440-1 are 380 in real HP is that around 40-50 ?

 

[Budnicks]

There's a lot better ported head out there
maybe have yours reported/better, larger valve etc.
or are they maxed out ?
not really 100% familiar with the SRs, most of INDYs stuff

An out of the box (OOTB) AFR 270cc CNC ported flows 350cfm ranges,
at 0.800 lift
there's more room for more CFM too
they are optimized OOTB for displacements up to 572cid
to about 7,000 rpms as they come from AFR
(Now owned by Edelbrook)

Edelbrock MoPar BBW Victor, MW port
fully professionally ported, competent professional can easily flow 400cfm+
needs lots of special parts, no more than the SR's do thou

another 40cfm (over the current 360) is like 2.14 per/cfm x 40cfm = like 85.6 net Hp

345-350-360 cfm is nothing in the HP world, BBM or otherwise
not when you start dipping into the mid 9's or trying to go 8's NA

that's always been the biggest choke point/HP robbers
in Wedge/MoPars heads
a Small-Block style/designed head & ports design on a Big Block

Hell
a run of the mill Rectangular Port 'Iron BBC heads' can do that easily,
that's part of why they run so well (I know sacrilegious)

take even some more weight out of that combo too,
even at 3400+ #s, it will help ETs & MPHs also
a better converter ?
maybe different gears (only 136 mph) ?
or suspension may also, better shocks
taller or bigger/better tires, different compounds ?

Really hard to say, without seeing some runs & timeslips
or knowing exactly 'what's in the current build'

more camshaft ?
only 0.700" gross lift (or more rocker ratio) will help too,
if you have valve clearances
that thing runs 'pretty well' for what it is

N20 with the proper rings gap etc., easy peasy, a lot less $$

 

[65CopCar]

How much power you want? I went from SR headed 528 786 hp to 574 B1MC headed and 1060 hp.

 

[RemCharger]

You can put a max effort -1 program into an SR, correct? But there's power in the raised exhaust port of the dash 1.
I don't see a significant change in this upgrade

 

[ozzymaxwedge]

You can put a max effort -1 program into an SR, correct? But there's power in the raised exhaust port of the dash 1.
I don't see a significant change in this upgrade

Don’t think so, -1’s have a straighter port that’s why you need offset intake rocker

 

[dvw]

More compression, loose some weight. What rpm do you run it to now? What duration cam? Mine is about 300lbs lighter, 580", 15-1, -1's, 440-25 Indy crossram, 2 4150 Holleys, 285/292 112 LCA cam. Been 8.96@150. Will run 9.0x in about any weather. With available heads if you run enough rpm the cubic inch difference may not mean a bunch.
Doug

 

[ozzymaxwedge]

More compression, loose some weight. What rpm do you run it to now? What duration cam? Mine is about 300lbs lighter, 580", 15-1, -1's, 440-25 Indy crossram, 2 4150 Holleys, 285/292 112 LCA cam. Been 8.96@150. Will run 9.0x in about any weather. With available heads if you run enough rpm the cubic inch difference may not mean a bunch.
Doug

Hey Doug,
Cam is R280 4468-8 , 446 lobe x 1.6 is 713 gross and 690 net lift .
We go through though traps at about 7200-7300 rpm.

 

[ozzymaxwedge]

I do have another new cam here that I picked up in a group of other parts, it’s a Comp roller 289 289 108 and would be 716 lift

 

[Tex013]

Im going to go another way in thought . If you still have a factory block why not put the money into a 4.5 bore block , maybe aluminium . Even if using your current top end ? Drop weight , pick up cubes . Big bore will definately help . And give you room to change top end later for even more gains .
I mean how much is a new top end going to cost ? As opposed to block @ US$7000 . Not forgetting possible changes to rocker gear etc with head change .
If its in the Val i'd also look at a mini tub for a bit more tyre .

Tex

 

[Cranky]

Im going to go another way in thought . If you still have a factory block why not put the money into a 4.5 bore block , maybe aluminium . Even if using your current top end ? Drop weight , pick up cubes . Big bore will definately help . And give you room to change top end later for even more gains .
I mean how much is a new top end going to cost ? As opposed to block @ US$7000 . Not forgetting possible changes to rocker gear etc with head change .
If its in the Val i'd also look at a mini tub for a bit more tyre .

Tex

I'm a fan of big bore engines......and kinda like short stroke engines....

 

[Tex013]

I'm a fan of big bore engines......and kinda like short stroke engines....

im more thinking 540 or 572 ci
no replacement for displacement .

Tex
PS my World iron block added 90lbs but runs the same et & mph as factory block plus doesnt drop power as it gets a bit warmer in later rounds or hot days .

 

[Cranky]

im more thinking 540 or 572 ci
no replacement for displacement .

One way to make a smaller engine act more like a bigger one is to turn more rpm with it...

 

[33 IMP]

One way to make a smaller engine act more like a bigger one is to turn more rpm with it...

....but that only works if the big engine can't turn the same rpm.

 

[Budnicks]

I'm a fan of big bore engines......and kinda like short stroke engines....

& allows for higher compression, even with a less aggressive flat top,
especially w/zero deck

Pro-stock combo
4.60" bore 3.75" Stroke = 498+cid 11,000rpm+
albeit higher compressions
with much lighter rotating assemblies, will spin up faster
(limited to 10,500 rev-limiters/kill boxes by NHRA)
the bigger bore, 'allows' the heads to flow better too
allows for a bigger intake valve/s too
with lil' to no/less shrouding by the edge of the cylinder walls/bores

like with the 4.250" bore of a stock 383 or 426 wedges
or even smaller bore of the 413, 361
(you need to notch/grind the top side of the deck/cylinder,
on intake sides to de-shroud them)

even with the bigger std bore 4.340" 400/or 4.320" 440
will/can effect intake valve shrouding on better flowing heads,
with the bigger valves

 

[HardcoreB]

Thanks for the replies,
So if the SR’s are 360 and the 440-1 are 380 in real HP is that around 40-50 ?

There's noticeable power to be had going -1 with a 2.25 valve and if you upgraded the rocker gear to a paired rocker system you could put a big cam in it which would be worth more. Then again how well sorted is the parts combo you currently have?