Cylinder head swap

[Gunmetal5oh]

the 6al rev limiter will not "override" the computer, but the 6al will still work before the 6250 factory limiter kicks in..so if you put a 6200 pill in the 6al for example, you'll hit the 6200 limit on the msd box first

Right.. got that, was just misinformed on the rev limiter.
Limiting at 6250 ain't bad, will certainly prevent my engine from lunching itself.

Srings.
What if I buy replacements that are the same diameter as the current springs??
As long as the retainers and locks match I'm in good shape, no?

Thanks

 

[Gunmetal5oh]

OK. NEW UPDATE.
Found details on the springs I believe are on the built '69 heads.
The other engine had Performer RPM cam and intake, and I believe Edelbrock springs to match the cam.
Edelbrock Part number 5722 - which is recommended for ALL YEARS.
Single spring per valve.
110-120lbs seat pressure
1.77" spring height
1.140 coil bind height

I get .630" lift to coil bind
.630" - .542" = .088" from coil bind

I'm thinking the springs that are already installed on the heads will work just fine.
The only difference between the roller and non-roller RPM kits is the cam and lifters. Springs are identical.
It supports a performer rpm cam at .520 max lift on exhaust side, .542 is so dang close (AND with LESS duration) I think it will be ok, what do you think?
Plus, they are ready to run as they sit!

Tried to find the spring rate but no bueno!! Not a lick of information anywhere on spring rates and I searched for a while.
Unless you know who makes Edelbrock 5722 springs, or a part number interchange I don't think we'll know the spring rate.
I want to run what works, and will be reliable. Won't too much spring tear up the valvetrain and cause my exhaust valves to recess into the seats?

 

[need4spd90]

according to summit's specs on those:
Installed Height (in) 1.770 in.
Seat Pressure at Installed Height (lbs) 120 lbs.
Open Height (in) 1.200 in.
Open Pressure (lbs) 338 lbs.

so..math time again
338lbs(open) - 120lbs(seat)= 218lbs increase over a distance of .570"(1.770 installed height- 1.200 open height=.570")

218lbs dived by .570" = spring rate of 382.45 lbs/in

.542" lift(X cam) x 382.45(rate)= 207.28 lbs + 120(seat pressure) = 327.28 lbs with the X cam at peak lift..pretty decent..i'd run those, you'll be ok..but know you KNOW

 

[Gunmetal5oh]

That valve spring calculation lesson was educational. Thank you
I will run the ported '69 heads as they are. Will try to get a video or sound clip when finished.