Bugman Jeff

I'm collecting parts for a Vortec swap. I keep reading that the stock springs aren't the best. I'm going to be using a Summit K1103 cam in it. Looking through spring size/weight specs, it looks like the K-Motion K-700 springs should fir the heads and are only 30 Lbs heavier than what Summit recomends for the cam(464 VS 430). They're also only $50 a set. Has anyone had any experience with these springs? Are they a good match for the vortec heads and Summit cam? What are the other low dollar alternatives? I keep seeing the "Z28" spring recomended, but no one ever says where to get them or lists a part number. How do those compare to the K-motions? Thanks for the info.

MotorHead

Why don't you want to use the springs the cam manufacturer recommends ?

Solid LT1

Vortecs have a short installed heigth and I would consider running "beehive" springs instead of the K-700 springs. I think your seat pressure will be too high if your running std Vortec valves. Also the retainers and keepers on Vortecs are pretty cheap, I wouldn't use them in a performace application.

cam cooper

I have exp. with k motion springs used to be good now there cheap china junk buy good springs.comp,isky,etc

Bugman Jeff

Won't fit unmodified Vortec heads, the ID is to small by .005".

Rotonda

I used a Crane 99846 H-11 steel spring with stock retainers and +.050" valve locks for a 1.750 installed height. These springs fit over stock vortec valve boses and allowed me to use a .480 lift roller camshaft without worries. They are pricey.

jackson

production vortec springs are AOK for 1103 cam ... that cam nearly same as in gmpp crate 350HO 330hp & it has plain production vortec heads & springs. that spring gm p/n 10212811 . this should fit AOK ... but much more cam w/ vortecs is primary limitation at production vortec RETAINER ... there's a bulge on underside just around the valve stem & that moves real close to top of VS seal ... but it should be ok LESS THAN .475" valve lift. If used heads, suggest a fresh set of production vortec springs & fresh seals ... probably cheap on fleabay ... maybe cheap right there at your hometown gm dealer. this matter addressed zillions of times prior.

ya don't need pricey springs w/ 1103 cam in street motor

FYI ... I've posted z28 spring p/ns before:
sealed power p/n VS739R
elgin p/n RV943X
comp p/n 981

jackson

FYI
just put a gage on two stock unmodified production heads & measured bottom OD of guide boss

old iron sbc 400 head about 0.770" or less

iron sbc vortec 350 head about 0.870" or less

your conditions/results may vary ... y'all do the math on which spring ID fits what head OD

Solid LT1

Other alternative is late model LS1 beehive setup, but your still shopping for retainers and locks. Like I said before, I wouldn't use OEM Vortec stuff in a HP motor not even a 6000 RPM one.

jackson

GMPP includes that same vortec 10212811 spring & same retainer 10241744 & same keepers 24503856 & same 24502476 cam in its CT350 sealed race crate p/n 88958602 ... its most popular race crate ... dunno how many tens of thousands in service? ... they're very reliable ... plenty go 3-4 seasons without part(s) replacement/freshening ... am unaware of any wide-spread failure of any sort. Somehow, GM has it figured out.

Shark Racer

Honestly, would you buy Vortec heads if performance was your ultimate goal?

Rotonda

1) If you are looking for vortec springs, I have a set of brand new take-offs. Cheap. PM me.

2) Retainers - When installed, I found Comp Cams retainers to come lower down the valve stem than stock. That's why I'm running stock.

Solid LT1

There is NO WAY that those springs are the same as the ones used in the production truck Vortec head, maybe a marine use spring but, the truck springs are WEAK! I wouldn't use the truck retainers/valve locks on any motor I would build or drive hard but, I'm a pretty hard driver. If you want to save $100 for a set of springs/retainers/locks, so be it, I wouldn't!

Bugman Jeff

Thanks for all the info. Just the kind of stuff I was looking for

MotorHead

What you want to know is seat pressure open and closed, not spring rate and then you start to figure out the rest.

Part Number: 99848-16 BACK TO LIST
Outer Diameter Top 1.255
Inner Diameter Top .870
Damper NO
Seat Pressure @ Installed Height 114 lbs. @ 1.700
Open Pressure and Height 340lbs. @ 1.200
Coil Bind 1.153
Average Spring Rate 432 lbs./in.
Maximum Net Lift 0.487

K-700 1.265 diameter single Chrome Silicon spring that is good for camshafts
with up to .500 valve lift.
120# @ 1.700 - 375# @ 1.150 - coil bind @ 1.050

sickstysevin

Honestly, because for 150 bucks a set off a truck, car craft has made 420+ horsepower out of the box with a few gm performance parts, with a little work they are getting almost 500 foot lbs of torque. All of this below 6000 RPM, you get the benefits of one of the best factory port designs from the lt head, but you don't have to run the crappy lt configuration with the worthless, problematic distributor location(vortec intakes for carbs are under 150 bucks) or an aggresive profile high lift cam loosing engine vacuum. The vortec has superior flow characteristics to almost all gm factory production heads in the .200-.400 lift range.

heres the proof in black and white.

http://www.chevyhiperformance.com/te...ild/index.html