Most of you have more 283 builds than the ONE I'm doing now so here goes. I already have the parts left over from various other projects in my past life and yes, I do have 400 blocks on stands already but I NEED a 283 for cruising and occasional 1-2, 2-3 shift at a fun rpm. Block is fresh at .060, flat Speed Pro forged pistons. **** rods with the 2000 series bolts. Block has tool steel bars across the center 3 caps and studs, line honed. Heads are 461's with 2.00" intakes and 1.55" exhaust. Heads milled to 56cc. Did just enough peeling on the chamber walls to make the chamber on the intake side match the cylinder bore. Quench height will be .035 with the gasket I have and compression is right at 9.5:1. I have a clone of the '097 cam and Crower lifters with the EDM face oiling. Everything I've read says that even stock these things would rev. What valve springs did they have? I have on hand a set of the Chevy springs with an Orange stripe. According to the way out of date Bowtie catalog these springs are 110# at 1.70" and something like 358lb rate. Am I in any danger using those springs if I should accidently let this thing hit 7k? I'm just trying to use up parts I already have laying around. Oh, intake is the 350/365hp 327 aluminum piece.
I'm still giggleling at this! I love 283 threads, especially ones where the OP has lots of old parts to use. I hope he gets an answer for His valve spring question.
Duntov cams weren't really wild and, consequently, didn't need a lot of spring pressure. What are commonly marketed as Z28 springs will do the job. No point in wearing out the cam with spring pressure that you don't need.
How 'bout wait just a bit until I have the block back on the stand and it's going together. Nothing special with the intake. It's a L79 intake that some clever tool ground the Winters snowflake off so I got it for $75. Needs the bottom and sides milled to work with the cut heads. Then I'll re-create the casting mark to make it look a bit more original.
I've had most of these parts for almost free or collected them several decades ago. I want a Gen 1 SB for this project and it needs to wind a bit more than all the hydraulic cammed "crate motors". So no, not cheaper to just buy a motor. Have a 40' storage container of parts that I'm turning into ***embled motors, ect. Old fashioned hot rodding, work with what you already own. All that and my machinist has a dyno and nothing beats running in a motor you built and getting the printout for bragging rights. Beer may be involved.
Kind of what I'm thinking. I'll reference the old parts #'s and find the specs. The springs I have came in GM parts boxes and have the orange stripe so I'm pretty certain they'll work. I'll have the pressure checked to be sure. Can't just throw them away, gotta find a home for them.
Sarcastic response to a “283” or rebuild thread. It always gets brought up so that has to be here So far no “you’re better off with a 350” has been mentioned ……..yet. But hang on, it’s coming. I also have a 283 on the stand. Just installed Elgin “z28” springs.
I love all this great info on 283 builds. That is what I'm going to run in my RPU project. I get a kick out of the "you know it's cheaper to put in crate engine or just build a 350" comments on this forum. In the world of the SBC isn't the 283 a tad more traditional? If I was going to put in a crate motor I'm pretty certain I'd feel too much guilt and shame to mention it here. Please keep this 283 stuff flowing. I'm here to learn!
Yes, I drilled part way through and tapped the holes. Using aircraft hardware with safety wire to lock in place, I'm a airplane mechanic(A&P) by trade. Corvette windage tray and trap door pan.
Exactly, this one is going into more or less a period looking '65 vette. No original car was harmed in this production. Think road legal(kind of) with 4.11's, 4 speed and half height windshield roadster about 2500lbs.
My first thought when you described the bars on the caps was great place to add holes for a windage tray . That said how many factory two bolt mains have we ever seen fail on a 283 SBC even with a blower or other big power adders? Cant hurt much and yea great way to add a tray with out special studs with nuts . I have aluminum rod 283 dragster motor from the 60's that ran nitro that has some custom caps and yet is still 2 bolt . I hope to resurrect it some day even though I have zero knowledge on how many runs those rods have had on them . I'm guessing its about 13 to 1 by looking at the piston domes . A 4 speed 283 Vette. I almost went that way with my 57 Vette .
Motor Manual lists the valve spring on the seat for a 270 hp 283 @ 69-70 psi. If your valves are not under cut they probably weigh more than the 1.87” which were stock. With the larger valves you also lost some low end torque but it sounds like that’s not a concern.
Not so much worried about blowing up, more about I was going to line hone for studs so why not, can't hurt and only help stabilize the caps/bearings.
Valves are undercut and backcut, every little bit helps and my time at the valve grinder is close to the shop fridge. I've built more than a couple SB Chevy's but have NEVER used a solid flat tappet cam. If a hydraulic flat wouldn't get it done I'd pull a hyd. roller or solid roller off the shelf. Never had the need for a solid flat tappet cam. My favorite is a hyd. roller with solids drilled for pin oiling. Lash it tight and let it spin. Found the specs for the springs I have and looks like they are plenty without being too much.
I have a few of them myself that I'm doing things I shouldn't do to a 283 but so is life LOL! I like the direction of what you have, my problem is holding myself back since I own all the equipment to let myself play! The Z/28 or Orange springs are a basic all around spring. Pretty sufficient in most cases. The last flat tappet I ran in 2002 era had 180# on the seat and around 500# open with an EDM lifter but I was turning 8500 RPM with it in our Drag Car. That camshaft you should be fine with that style of spring. If there is room before coil bind you could always shim it up a little more to increase the seat pressure some.
Nick I bought a pair of NOS 291 head castings, OEM machined for 2.02 valves in the late 80's, late 67 cast date, the box was labeled "initial 1968 Corvette stock". Included were boxes of NOS valves, springs,"O" stamped rockers, retainers, keepers, etc. I was putting my 350 hp 327 together and at the time I didn't know that the springs were for the offroad camshaft, my engine machinist wanted to kiss all the valves and seats and check the springs, he said the springs were too much for my cam, so I took them to the Portland Swap Meet with some other parts, it was early and I hadn't marked them yet, guy picks them up and says how much, I shook my head and just threw out a number of 200 bucks and figured he would set them back down but he didn't even flinch, sold. I see they now are going for over twice that amount.
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