Chevy valve springs

[pagrunt]

I'm working with a matched set of Chevy 041 heads that looks like an older rebuild. They have what looks like GM screw in studs (not set up for poly locks), double valve springs (exhaust with a blue stripe, intake with a red/orange stripe), & a rough measure of 1.94/1.50 of the valves. I would like to know what the rate is on the springs or if they are even OE/OE replacement. This is a challenge since there is no guide on how any are marked. The "back story" I was given was they came off a bone yard engine that was described as a 302 cause of the crank flange & pistons. Of course he got them in the late '80's/ early '90's, remembered those details but didn't know of the screw in studs. It would be cool if they were real DZ alt number heads rebuilt to spec, but the valves don't back it. Hope someone out there can help so I can figure out if I should use or replace the springs. To help, I am planning to run a cam like the Eldelbrock 2102.

 

[lilbowtie]

Do yourself a big favor and buy new springs that your cam requires. You don't know how old or fatigued or even if they match your new cams requirements. Looks like your going flat tappet so If your cam requires double springs remember to leave the small one off for the break-in. Lube up the cam & lifters w/ break-in lube on install and always use an oil w/ high zinc

 

[64nailhead]

X2^2 with lilbowtie. Springs are cheap, but weak ones will do their best to ruin your new cam via floating. And based on your story of how the heads came into your posession and the 'story' came with them, I'd be willing to bet you that those springs are marginal at best. With that said, most any machine shop worth there salt can measure the seat and nose pressure of those springs or any spring for that matter. Also, attempting to use those heads without having the guides, seals, valves, valve stem protrusion, and spring installed height set is recipe for sadness IMO. I say this based on experience as I've made the same mistake in an effort to save a buck. And then, to add insult to injury, I spent $600 getting a old set of iron heads reworked. They were on the motor for a year and a half, then finally did it right and put on a set of aftermarket heads. Threw out about $750 total, then dropped $1100 on a decent set of heads.

I'm not attempting to be pessimistic towards your build plan, but rather trying to keep you from making the same mistakes I made.

 

[pagrunt]

Thanks for the input, this is helping with the pros & cons of the unknown. I am looking at doing a matched set up on the valve train for a mild build. If it wasn't for the budget a new set of heads would be ordered. But you add setting up the new garage, replacing cheap tools, upgrading old ones, & working on other things the car needs just kicks you in the you know what. After I get the heads stripped I'll be able to see what I'm looking at what was done. Like I posted, I plan to run something like an Eldelbrock 2102, springs to match, and 1.5 roller rockers. Not looking at the top dollar stuff, just the good stuff to find those hidden horses.

 

[lilbowtie]

Those heads are going to be good for low - mid range power and that cams fits the bill. I would invest (if you don't have) a valve spring micrometer to set the valve spring heights to get your proper open/closed pressures, and read up on valve train geometry - Comps Cams web sight has a good learning center click on that and go to their tech info. It's the little things that need attention.

 

[64nailhead]

X2 with those heads will be fine for a mild street build (300HP), but I'll bet that you'll find that by the time you have worked (vavle job) and fix what is wrong with them that you'll be into ti for all of $500. You can buy a set of ready to run aluminum heads ofr another $250.

Why don't you give us some idea of what your up to other than with the heads. HP goals, application, what you have for a block and rotating assembly, and your budget. The kicker to get it run the way you want is to come up with a plan of matched parts, then budget for that and stick to it. You'll be much happier in the end.

The only time I go against that mentaillity is when someone is building a motor that's only requirement is to get the car from point A to point B reliably - the OEM stuff is really good for that..

 

[pagrunt]

I'm working withe a '70 350 block (010 cast, 4 bolt, 010/020 content) that I just got back from the machine shop. Just needed cleaned, everything was good. It was a CRE code (300/TH350). My plans is to put 300 at the wheels if possible. As I posted I want a cam around the Eldelbrock 2102 specs & use 1.5 roller rockers. I'm using a Performer intake with a Holley spread bore. The pistons/rods/crank are stock. The exhaust will be 2.5", but I'm on the fence for using the new Hedmans I have or stock manifolds for this engine. As for the heads, I want to clean them up, have the shop check the pressure & height on the springs. The engine will be backed by a 4 speed with 2.85 1st and a 2.73 rear. I want it to be a cruiser but to be able to put my foot in it when ever I want.

 

[64nailhead]

300 crank HP can be done with the headers. Without the headers it will be a much taller order with a basic stock head. Be sure to keep you quench below .045".I still highly recommend a set of aftermarket heads. Hopefully your machine shop give you an accurate assessment of yours.

But geesh, those 2.73 gears are going to stink (IMO). Are you intending to stick with the stock tires?

 

[pagrunt]

When they get the heads they'll be checked out for what might of been done by another shop. For the Hedmans, they are a set of Elite 68318. But I just figure at times a set of manifolds will be OK since the last set of standard Hedmans rusted out. As for running the 2.73 gears, I decided that since I'm not racing it I don't need anything special. For the tires I'll be riding on 235/60/15. Maybe after 26 years of ownership, just want it to be simple.

 

[pagrunt]

Was able to do a better job looking over the heads this morning. The springs are about 1.460-1.465 O.D, the seats were machined & shimmed. They all have a red & blue stripe painted on opposite sides. I going to be dropping them off at the machine shop to get a better look & check the spring rate. I didn't see any signs of porting being done. What ever they were on was ran hard from all the carbon in the chambers.