Just buy new springs !! If the springs are that big they are probably double, that cam will need a smaller single spring. You might have to get new retainers and or seats. Are you going to run rotators?? The carbon doesn't mean they were run hard - someone didn't know how to tune their set-up. You can also use poly locks if you want. Seeing your farming out all your head work you might want to take Nailheads advice
Chevy valve springs
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The springs are doubled & I have been pricing ones to work with my cam just in case the are too stiff. I have to get new rotators for the new ones unless I part out the 305 heads (not to hip on doing it that way.) As for the screw in studs, they are OE type with out the flat spot for the poly locks to do their job. The heads are just getting checked to make sure they are serviceable, I plan to do as much work that I can to save on the budget. If I could, new heads would perfect but the shoe string can only stretch so far. If this was 20 years ago Summit & Jegs couldn't be able to get me the parts fast enough.
Double springs at 100lbs? Sounds pretty light for double springs. If they do much of anything beyond stock builds, then they should be able to hit you with spring pressures for seat (installed height) and at .500". These are the numbers you're looking for. The next question is how are the guides? How's the valve job? 3 to 5 angle with the throats cut?
And you are aware that a set of stock Vortecs will outflow these by 30 cfm. But with some keen porting these will run comparably to Vortecs.
Get an idea out your machine shop for a cost and we'll see if you might find something in the some range.
You still haven't hit us with any short block info - namely piston to deck clearance and piston cc.
And you are aware that a set of stock Vortecs will outflow these by 30 cfm. But with some keen porting these will run comparably to Vortecs.
Get an idea out your machine shop for a cost and we'll see if you might find something in the some range.
You still haven't hit us with any short block info - namely piston to deck clearance and piston cc.
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The short block is stock 1970 CRE that will be running an Edelbrock 2102 cam. The rings are Hastings moly. The pistons are the original 10.25:1. The block & rotating assembly was gone over to ensure everything was well in spec. As for the springs, they are tested at 100/400 lbs. I have never thought to ask if the heads had any extra machine work out side of the spring seats & screw in studs. The guides are good. I know there are a lot of heads, stock & aftermarket, that might be a better choice but the budget drives what I use. The shop doing the work does some of the local dirt racers engines & been at it for close to 40 years. I should sit down & do a build thread on the whole car one of these nights to give an idea of my overall plan.
'100/400' - if this means 400 nose or max lift pressure, then that is too much. Most FT cams are looking for 280-295 for low RPM, mild lift, street use. And I'm not clear as to what you are describing for your pistons as 'original 10.25:1'. Do gave any idea of the cc or compression height? And 1970 CRE also draws a blank from me - are you implying a 1970 stock 350?
Nailhead - I believe he has his mind made up and your not going to change it. looking @ the cam specs spring seat pressure is 80lbs @ 1.700 and 200lbs @ .475. By the way the required 5802 springs don't take rotaters.
The entire build sounds a bit sketchy. And if the those springs are indeed what he stated, then I'd give that cam 2000 miles max. Hopefully he's repeating bad or misinformation - for his sake. Hopefully his machine shop guy(s) are reputable. I do truly wish him the best of luck.
Short block-1970 Chevelle/Monte Carlo/Camaro/Nova 350 c.i. CRE TH350 300 h.p. stock compression ratio 10.25:1, GM piston 3892673, GM crankshaft 3941182, 4 bolt block 3970010, Melling standard oil pump, Edelbrock 2102 camshaft, Comp Cams double roller timing chain set, 1969 3947041 1.94 intake/1.50 exhaust with harden seats, machined for larger O.D. springs, 1.460 O.D double springs, 100 lbs/400 lbs, 1.5 stamped roller rockers, Edelbrock 3701 intake, Holley 9895-1 carb, Proform HEI distributor, either stock iron exhaust manifolds or Hedman Elite headers.
You have a great short block - I run a stock L-82 short block(identical to yours except 464664 pistons) and I'm pulling 450 Hp. Please do your homework on those springs and that's all I will say. You asked for advice and I got 4 agrees on my first post which people usually don't check.
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