Looks like Im picking up a brand new in box set of 077 heads

Going back and forth of putting together a mock 427.

-Need cam specs and most of all seat/closed, open pressure
-Will be doing the upgrades ie helicoil on stud bosses, possibly larger valves, will port myself.
-If this build happens am hoping not to exceed max pressure so I can run some type of solid roller...or may still use a FT just updated specs.
=Want a max power street rat that wont rip the stud bosses out of them.

-Which engine designation used the alum heads and alum heads there were a few?

Anyone got a ZZ427 block for sale for working guys $?

 

Specs I got from Crane
ZL1/LS7 Crane Solid 298 308 110 3 262 272 0.575 0.615
advertised dur/adv/LC/Advanced/.050 duration/.050/Lift/Lift
Says power range 4400-7200
It's their Blueprinted series #3959180
they reccomend springs 99893
130 lbs seat @ 1.850 / 402 open @ 1.150 / 0.710 max lift / 391 lbs/in. rate

Those springs should give you no problems on 077s, but run the longer ARP rocker studs to be sure

 

Thanks....Ill have to find the stock Z closed and open pressure, compare.
Dont want to rip stud bosses out...afraid a roller will and dont really want the cost.
Was toying with finding a good sim program to compare what I want to do and have before making a final decision.

 

Here's two pieces to help:

• My build cost all itemized - I had to buy almost every component
• My spring rate 240/450 on my 074 L88 heads

My builder has built thousands of racing BBs over 40 years and the 074/077 heads were the hot ticket for the racers back in the day.
He said they really never had problems until the rpms and spring pressures starting getting extreme like 550-650+ They just recently killed a pair of heads like that but the springs were like 850 and the rpms at 8000+. He built mine with an LS6 like solid roller and it has survived 10 dyno pulls to 6500 so far just fine. He swears it'll be fine for years.

 

240 on the seat, no wonder they could have issues. My solid roller takes 20 less!
Thanks for the info I appreciate it. To get the most out of these sounds like guys would put larger valves and port...the intake port (sounds like) doesnt respond a lot without the upgrade...
No clue on power Id want...more top end than I have now and noticeable improvement on tq across the board would do it.
Can only get so much to the pavement...burnout machines never impressed me.

one thing I love about SFT cams is if you get a quality piece (thats an issue), broken in right imo they are less to worry about..no needle bearings
I plan on doing some around town errands...and if I wanna cruise 100 mi to the beach and back it will do it.
Ran my 70 Z/28 for yrs like that and never had a problem.

 

The race 074 heads that broke were on an 8000 rpm 580 cu in near 900 HP, alcohol, drag motor
275 dur @.050 SR at like .730 lift; power range 4500-8000
springs 340# seat to 730# open

They had a few hundred runs on them. Also a Stud Girdle. But yeah they eventually broke.

I have pics somewhere of how they broke if interested.

 

Spoke with Guy at Crower just now, he recommend a 252/262 (or 3?)@050, touch over .600 lift on a 107
They are a little on the conservative side and I tend to overcam.
Suppose its a contender, Ill wait to hear from Ron at Isky

He was familiar with the head and kinda knew where I wanted to go. Old timers >kid reading down a chart every time

 

Go SFT and be sure get the EDM drilled lifters. That, and good oil should make sure the cam lobes last.

 

Thanks..he recommended their 01-351 Cool face lifter, probably the same you mentioned
Cam lifters were around 350 w/spring kit was 5xx.

 

Cannot go wrong with Isky or Crower in my opinion. Running Isky solid cam in my C4 and one in my 455 Gto.

 

Sounding better. 252 is plenty of cam. The 262 of a ZL1 cam is designed for open headers and absolutely strangled by exhaust. Like -100HP or more.
The 107 LC will put the overlap back and make it bark.
The 074s (mine) and 077s (yours) really don't flow that well. The exhaust is very low flow it gets reversion easily and stalls out the HP.
Here are mine that I had flowed. Almost stock, very little porting. A little pocket porting, a little blending, flowed about the same as what I found on the web.


Anything you can do to help the exhaust out is a plus. My 074s have the round exhaust port which is really bad. The 077s were an improvement, so should have the D port or the W port. (I hate to say it, but even stock Oval ports make more power in a street car with mufflers than mine.)

I use DeskTop Dyno 5 (ver 5.10) simulation software. It is amazingly accurate if you use real head flow data.

On my 500HP LS6 (as dyno'd) the 074 heads (round exhaust) choke it up so bad that if I change it (in the software) to open headers, a tall single plane and a Dominator I gain only 20HP. WTH !?!? But if I then drop a set of Ovals on it soars another 40HP to 550, and then a set of 325 AFRs it climbs another 75 to 625HP !!

That's 125HP with 4 changes, most of it in the heads.
It's all because of the lousy exhaust port. That's why 500HP BBs were all there was back in the day, and why we can get 650+ today, head technology has changed a ton.

But I don't care. I wanted the look of the L88 heads, and this thing won't hook anyway with stock street tires LOL!


If my bosses ever break, I'll be pissed, but I'll toss a set of AFRs on there in a heartbeat, and have to "settle" for the extra 70HP thru with mufflers.


,

 

You can't compare crappy 50 year old solid lifter cams to modern cam profiles.

 

compcams improved version
https://www.compcams.com/nostalgia-p...k-396-454.html

 

Thanks RR....I know solid rollers are better but dont feel like destroying these heads
Ill have them flowed after al the works donebefore making a decision
Still have to talk to Ron at Isky, either company is fine with me. Have a custom Isky SR now and love it
Hoping with a alightly smaller cam and better breathing it hits well and carries power far enugh.
I can always go afr thats too easy though. Richard & Dave at West Coast Cyl heads are willing to do a bang up valve job...those guys got their acts together....bought my Dartts from him back in 2000. Nice guys

 

Apparently it costs the same at compcams to custom cut a cam if its already in their profile. You could have them mod the ZL1 cam to be a retro roller. Worth looking into

 

use a stud girdle to support the studs

 

I’m not a ZL1 expert but I also want to maintain that certain look. I’m running 1967 L88 heads with a CompCams solid roller. Really mild spring pressures. When I had the heads surfaced the machinists told me not to run too much spring pressure because, back in the day,

1967 Winters Castings


the studs would break off. My 427/390 block got trashed so I installed everything on a Dart 540. With the extra cubes I’m done at 5000rpm. With a 427 you would have to spin it to 7000rpm.