Head & cam selection...346 iron w/solid roller or Indy EZ w/XE285HL

-

IQ52

Well-Known Member
Joined
Jul 30, 2011
Messages
2,870
Reaction score
3,068
Location
Idaho
The thread on a head and cam selection for a 440 got me to thinkin' about some old 2014 dyno tests we did on a 8.9:1 compression 440 with 2355 pistons. I thought I had burned the old dyno sheets but there in the corner was a dusty yellow folder with a stack of 80 dyno runs.

So then we have two dyno runs both with the same short block.....
.....#1 top end) 850 Mighty Demon, 2" 4 into 1 Super Sucker, on a single plane Mopar Performance M1 & solid roller 277 @ .050, 105 LSA, .608" gross lift w/1.6 rockers, 346 iron heads flowing 295 cfm @ .600" lift. (Edit: 8.9:1 compression)

.....#2 top end) 850 Mighty Demon, Edelbrock Victor, Comp XE285HL 241/247 @ .050", .581" gross lift w/1.6 rockers and solid lifters @ .005-.006 hot lash, ported Indy EZ heads flowing 350 cfm @ .600" lift. (Edit: 10.4:1 compression)

Which will make the most top end power? By how much? What is the maximum power level?

@ 3,500 rpm
.....#1 made 537 lb-ft.......roller cam/small heads
.....#2 made 508 lb-ft.......hyd flat tappet with solids/big heads

@ 4,000 rpm
.....#1 made 530 lb-ft
.....#2 made 527 lb-ft.......somebody is catching up

@ 5,000 rpm
.....#1 made 502 HP
.....#2 made 518 HP hmmmm

What happens now........will the trend continue?

@ 5,500 rpm
.....#1 made 552 HP
.....#2 made 544 HP.......guess not, but how close will they stay?

............................#1 HP.........#2 HP
@5,800 rpm...........571............544
...5,900 rpm...........582............564
...6,000 rpm...........594............581
...6,100 rpm...........587............576
...6,200 rpm...........600............574
...6,300 rpm...........596............583
...6,400 rpm...........602............588
...6,500 rpm.............................595

Funny how the different cam and head combinations work themselves out. Gotta have a lot of respect for the XE285HL with the right combination. Here it went to 6,500 rpm when it is rated 2,500-6,200 rpm. Not that that really means anything I guess.
 
Last edited:
Nice side by side comparison. Truthfully, both combinations are making great power! 65'
 
Both sets of heads had the same chamber volume?
Whoa, good question. Forgot to mention the difference. With the iron heads we were at 8.9:1 compression and the Indy heads gave us 10.4:1. Will edit original post.
 
Wow, cool comparison. Thanks for posting this.

May I ask how the torque curves compared? I am assuming combo #1 looked just good or better in that RPM range.
 
Wow, cool comparison. Thanks for posting this.

May I ask how the torque curves compared? I am assuming combo #1 looked just good or better in that RPM range.
Interesting enough, during these tests, #1 averaged 16 lb-ft less between 4,000 and 5,300 rpm. It's not a combination I would choose to run for myself. We just had those parts laying around when we did the test.
 
Once again showin that compression ain't "ALL THAT".
 
It would be cool to see what #2 would make with the cam from #1
 
man im even more confused now..why did more compression AND more cam make less power?
 
#2 was more heads, more compression, wayyyy less cam and it was a solid flat tappet instead of a roller cam.
ah ok, i didnt think it was that much smaller but im learning..lol.so tell me why a roller would make much more than a SFT?
 
Actually, it’s a fast rate hydraulic cam being run with solid lifters and very tight lash.

Just askin here, as I don't have any experience doing that, but are there any premature wear problems when doing that?
 
Just askin here, as I don't have any experience doing that, but are there any premature wear problems when doing that?
I haven't found any yet Rob. We ran one in a 383, used it in a couple of demo derby cars and then installed the 383 into a '67 Coronet station wagon, drove it around for years, ran it on a chassis dyno at Mopars at the Strip where it made, gosh, seems like 300-330 RWHP. Has a little blowby now but next it is going into a 4x4 '68 Town and Country station wagon.
 
I haven't found any yet Rob. We ran one in a 383, used it in a couple of demo derby cars and then installed the 383 into a '67 Coronet station wagon, drove it around for years, ran it on a chassis dyno at Mopars at the Strip where it made, gosh, seems like 300-330 RWHP. Has a little blowby now but next it is going into a 4x4 '68 Town and Country station wagon.
Sweet. I’ve ran them both ways. Hydro lifters on a mech cam and mech lifters on a hydro cam. No problems yet. Since 1984. Kim
 
I cannot find a recorded cranking compression for #2. #1 was 118-120 psi.
I think I remember reading about it, were the .100-.350 lift numbers fat on those 346's?
From what I know and how well you can work those I'm assuming they are a more mildly done than your usual 330's type 906.

Thanks for bringing this back.
 
I cannot find a recorded cranking compression for #2. #1 was 118-120 psi.
Just spit balling
118-120 cranking psi seems kinda low for that much of HP?
Could that be that possible?
 
What would one expect the cranking compression to be with an 8.9:1 static CR and a cam that’s 277@.050?

120 sounds about right to me.

My old 9.7:1 448 cranked 155 with a cam that was 259@.050.
 
I think I remember reading about it, were the .100-.350 lift numbers fat on those 346's?
From what I know and how well you can work those I'm assuming they are a more mildly done than your usual 330's type 906.

Thanks for bringing this back.
Some flow information on these 346 heads are in these two threads that cover some of the 80 dyno runs..................
'Pop's Engine' another 440 on the dyno.

Pop's 440 is near ready to dyno.
https://www.forbbodiesonly.com/moparforum/threads/pops-440-is-near-ready-to-dyno.64775/
I don't think anything we did there is spectacular. We just had fun doing it as a father and son team.

Cody has finish another set of 346 heads with spare parts we've had hanging around for many years and we will use them on a 450/400 we are making for our '73 Dodge Charger. And no, we haven't been able to duplicate the flows we have seen in 906 heads in others like 452, 346, 902 or even 915 heads.

915....wow....this just reminded me I have a set if 915's he mildly ported and I botched the valve guide clearance. A valve seized and bent on one of our dyno tests. I gotta drag those puppies out and repair them sometime. But boy is that storage unit COLD right now!

Just a couple of days ago he expressed some interest in maybe doing some more heads again. Then begged, "Please Dad, heads maybe, just let's not build anymore engines for people!"
 
-
Back
Top