qwank

I've been talking about a cam swap for years, and thinking about doing it this summer.

How would the Crane Cams 113801 cam work with my set up and the stock computer and carb? cam specs: Duration @ .050" Lift 222° Intake/234° Exhaust. Lift: .467" Intake/.494" Exhaust, 114 LSA

Heads: stock ZZ4. Will be about 9.8 cr . Exhaust: Hedman Long tube headers and custom sidepipes I welded up. Transmission: Richmond 5 speed with 3.36 first gear and 2.87 rear gears (equates to a muncie with 4.11s in the rear)

Thanks.

MelWff

You want a cam with an operating range of 2,200 to 6,200 rpm? Are you seeing that kind of engine speed? For street usage looking at the Summit Racing site it does not show that cam.
Here are two with a slightly lower max rpm.
https://www.summitracing.com/search/...4%2B4294891014

jackson

OP Qwank
Must you use L81 carb, dist & computer?

If YES, I'd ask Crane and tell them exactly what you're working with.

Also, there's a few guys on here who've done similar L81 upgrade ... wait for their feedback.

cv67

Old grind but I bet it works pretty well with what you have. 222 on the intake isnt big at all....n oclue on the computer
Have access to the valve timing events?

qwank

That first one is pretty close to the one I posted and the second one is pretty much the same specs as the L-82 cam. Biggest difference with the one I posted is the 114* LSA, which I'm trying to stay with to keep my computer happy. The first one make still work with 112 LSA and it does bring the rpm range a little lower where the stock bottom end should be able to handle it better. Thanks for the recommendation, I'l look into this one a little more.

For now, yes. I'm going to eventually switch over to fuel injection, but for now to keep costs down I want to use the stock carb and distributor.

As long as I make around 15 inches of vacuum the computer should be happy.

Engage

I don't think your computer will be happy with that cam.
I tried a comp cams he 268 on mine once.
Stock heads with headers ,intake..... could not get it to idle right very lopey.
Had to unplug computer and change carb and distributer to make it work

qwank

Comp has a 268 grind specifically for computer cars now with 114 LSA, but it's thier XE series and I've heard a ton of horror stories about them.

https://www.summitracing.com/parts/c...waAseHEALw_wcB

Jebbysan

This would be a great candidate for a stock L-82 cam....some roller rockers and real pushrods......
The L-82 is a great street cam......the issue on the L-81 as well as older 350's back to 69' were the crap intake and exhaust.....
On the ZZ4 heads.....make sure you have the right flat tappet spring......Elgin and Isky both make a version of the "Z-28" spring that is great to .525 lift.

Jebby

qwank

I'm not going to do roller rockers, I have the stock self aligning rockers from the ZZ4 so I'm going to use those, I don't think the cost for roller rockers is worth is for the setup I'm doing.

I also heard I should use a dual pattern cam with the ZZ4 heads since the exhaust ports were so poor, that's why I've been trying to find something close to the L82 cam on the intake side, but a little larger on the exhaust.

And I didn't know flat tappet cam used different springs than roller cams? the ZZ4 springs are good for about .510 lift, some say .525 but I'm not sure about that.

Jebbysan

Stock rockers are not worth the metal they are made out of and most of the time do not even have 1.52 ratio....more like 1.47 or worse, plus they flex like mad along with the spaghetti pushrods and should be the first things that are thrown away on a build......a set of one piece pushrods and Comp roller tip rockers is worth the money.
The ZZ4 was a hydraulic roller engine so the springs cannot be used...period. Elgin makes a set for flat tappet with springs,lock,retainers for $70. Actually the ZZ4 exhaust was the improvement.....the intake remained exactly the same....or worse. The ZZ4 heads will need a proprietary head bolt kit for the aluminum.
If you have them....fine, but I would not mess with them.....find a pair of used Dart Iron Eagle heads and bolt those on......those will show REAL gains.......you could pocket port and bowl blend them but you will still be 30 horses off an out of the box Dart head.

Jebby

jackson

JMO
Most upgrades need to be done in concert with adjunct upgrades; otherwise, piece-meal approach often ends up a real disappointment (turd).
Perhaps, save toward bundled FI & cam swap budget; run whatcha got 'till then.

As said, call Crane ... but there's more than one comp 268H ... there's also an HE268H ... gentler high energy HE series not same as extreme energy XE

call Both crane & comp ... tell em what you have and what you want to do.

those OE stamped self-align rockers serve quite well in ZZ4 crates and x603 aka CT 355 crate race motors.
Those motors all have same heads and their roller springs are
pn 12551483, Single, 1.320" OD, 101 lb @ 1.780", 332 lb @ 1.22" (rather puny for a "roller" spring conventional wisdom/intuition)
Actually, pressures@heights not so different than Z28 springs.

Elgin single Z28 springs std & +0.100" longer free length
RV-943X 1.250 OD, 110 @ 1.700, 285 @ 1.210, coil bind 1.160, max lift .490
RV-1943X 1.250 OD, 125 @ 1.750, 325 @ 1.200, coil bind 1.160, max lift .550

qwank

I forgot to mention the ZZ4 heads are not currently on the engine. Engine is still stock except for headers and sidepipes, and the Richmond 5 speed swap.

cv67

Be aware there are lots of "z/28" springs out there, trash coming from overseas..they are so cheap to begin with its not worth saving 10 bux

Jebbysan

The Elgin springs are high quality OEM spec.......no issue.

Jebby

qwank

So I really can't use the stock ZZ4 springs with a flat tappet cam?

jackson

Many have.

ZZ4 spring's pressures are rather similar to Z28 spring's.

Why Not?

Jebbysan

I was under the impression those springs were heavier than that....Hydraulic Roller springs generally are....
If those are the actual spring pressures then it should be fine...

Jebby

qwank

Thanks, guys. I'm pretty sure I already researched all this stuff a few years ago and I was good to go and just needed to pick an actual cam, So I was confused for a second there.

jackson

spring specs mid-page
https://chevroletperformanceparts.co...e_vsprings.pdf


brand new set of those 12551483 ZZ4 springs for $51 delivered
https://www.ebay.com/itm/NOS-Genuine...75.c100623.m-1

jackson

FWIW ... all iron head production (RPO L31 vin code 8) 5.7L Vortec motors came with small (.414"/.428") Roller Cam-Roller Lifters ...
... all those production Vortec heads came with this small Roller Spring pn 10212811 ... which is all of 80 lb on seat.


That's right ... GM pn 10212811 ... an 80 lb "Roller Spring"