I have a 1976 corvette 350 with 49000 miles on it I want to increase the power in it I just bought a comp cams cam and lifters with springs and timing chain has a lift of 426 and 469 with a duration of 262-270 also got a edelbrock rpm air gap intake with a 650 holly plus a set of edelbrock e street heads with 64cc is this a good combo I called comp cams and waited on the phone for 1/2 hr and the guy was no help at all was reading about the heads and says if I use a different cam then edelbrock and want to change the springs I would have to change the studs are the comp springs much ? stronger than the edelbrock ones since I bought the comp kit wouldn't I use the comp springs was also thinking of putting flat top pistons in it .

 

Did you ask Edelbrock what their spring pressure is and then ask CC what their spring pressure is, hard to answer your question without the numbers. With flat top pistons you may be raising the compression beyond the abilities of your local pump gas. Do you have an appropriate air cleaner assembly to fit that intake under the hood?

 

I have a dropped air cleaner have not built motor yet spoke to summit tec line cc springs are 370ibs and edelbrocksprings are 320lbs tech said to leave the edelbrock springs in it and it wont make any difference as long as im not reveing over 5500rpm im not drag raceing this car mostly want low and midrange and some top end. lots of mountains around ny Hudson valley, he also suggested to put some flat top pistons in it this cam is not that large its under 50.00 lift tech said with flat tops should put it around 10 to 10 1/2 compression all knowelage is greatly wanted .

 

anyone

 

save money and time, crate motor

 

You will save yourself a million headaches by going crate.

If you make a single change to an existing engine, you step into the engineer realm as you are in the process of building a 'new' engine.

The thigh bone is connected to the...shin bone. You change one thing, it will affect one, two, or more other things. This will even be true with a crate engine. At least by going crate you will 'get out of the engine' to troubleshoot problems.

ie. overheating, fuel supply, suspension, braking, etc.

Staying outside the engine will make things much simpler. If you want to make life complicated - then by all means, have fun with heads, manifolds, carb, timing, etc.

 

With flat top pistons and 64 cc heads you're going to be fighting tuning to keep it from pinging. Better to keep the compression down to about 9.5 with today's crappy gasoline.

 

why do people buy parts and THEN ask questions about them?

 

sorry for asking

 

I think that what everyone is trying to get across is that there are many ways to create an engine for our cars. The pieces you bought may not be the best choices as a package, but if you install them and can make some compromises in your driving habits it will work.

The small chamber heads will significantly raise your compression with the stock pistons. So run premium gas after you properly set up the distributor curve and initial timing. If you want to build bottom end you might want to trade the RPM Air Gap for a Performer. The carb is fine but your stock Quadrajet will work great with some minor tuning. The cam will be a little lumpy so your rear gearing might need some attention, especially with the stock automatic.

There are many guys on the forum who have successfully built a street engine from parts just like you are trying to do. After doing that a couple of times, most find that it is cheaper and easier to buy a crate engine. I personally built mine from scratch and like the results, but I've done it a few times. We all learn by doing.

 

Hi johnnyjaws, nothing wrong with asking questions. If we never ask how would we learn?

Anyways, for building an engine from your existing engine there are many things to consider. The main things are how much money do you have to spend, what kind of performance you want, how much time do you have to commit, and how much experience do you have with rebuilding engines.

In my case I didn't have the time or the experience to build my SBC into the performance motor that I wanted so I chose to purchase a crate engine. I knew that the engine builder probably could build the engine sooner and for less money than I could after all the mistakes that I might make during the process. Especially, since this was to be a 427 SBC which would include a lot of machining and custom work which I would need to have a machine shop to complete for me.

If for the most part all you are going to do is to bolt on new parts in place of the old parts then I would say go ahead as there is lots of info. out there on SBC performance upgrades. But once you get into machining the block or porting the heads etc. then I would say go the route of a crate engine for simplicity, time, and possibly cost savings.

JMHO...

 

the cam I bought has springs with 370lbs but on the e street head has 320lbs springs eldebroke says if I change the springs I have to change the rocker studs and may need meching for the springs also not to revover 5500rpms thalked to summit tech and he said to leave the e head springs init

 

Is this not the car with the fammed 335 horse engine?

 

Not with aluminium heads. He can run a higher cr with no issues.... he actually has a close setup to mine.... remember there's static and dynamic compression as long as the dynamic isn't too high your good. I have 9:6:1 with cast iron 64cc dart head a .27 head gasket for better quench and an undecked block with flat tops... I have the mild older 268h cam....engines still on the stand. Waiting to go into the car. But other with the same setup say its fine on 91 octane.
I love how so many discourage and promote a solution on a crate.... Its like saying. " sell the car and buy a new one... there's too many head aches with maintaining an old car fixing one thing leads to repairing another.... and its never gonna perform like a newer vette anyway"
I say go ahead and build it yourself ' grow from it and actually learn something about the car instead of just spouting off specs from the order form on your crate engine when a gear head walks up to you at a car show.

 

Dirty Harry always said 'a man has got to know his limitations'. I bought my `76 Corvette from a retired police captain. I don't think he could change his own oil and he isn't mechanically inclined at all so he had a new GM crate engine installed before I bought the car. They're assembly line motors with a consistent set of specs and they're a great solution if somebody doesn't really understand the mechanics involved or just doesn't want the hassle of building an engine the old fashioned way. I'm glad he went the crate engine route. I don't have to worry about mismatched parts and half-assed machine shop work.

Having said that, if I'd owned the car at the time I would have built the engine myself. There's no substitute for the excitement of firing up a fresh motor you put together yourself. It's a rush.

 

Just did that a few nights ago!

 

I'd say go ahead and break the cam in with the stock edelbrock valve springs, then drive the car for awhile, taking things easy for a few hundred miles, to let all the parts break in to each other nice. Then start getting on it, and see if you get any valve float. It's kind of a project, but you can change out the springs later if you decide the cam needs more valvespring.

Scott

 

This still doesnt solve the issue of the press in studs. There are you tube videos and a horse power tv episode that show how to convert to screw in studs, it dont appear to be that difficult. Or you could spend the money to have this and the springs done at a local machine shop. By the time you dothis youll have enough into the heads that you could have bought a little bettęr flowing head with screw in studs. You could put the etecs on a shelf and buy another head, but i assume by the head choice that this is what was budgeted. As far as pistons and compression youll need to use acompression calculator and a dynamic compression calculator to figure what piston would net you 9 to 1 or 9.5 to 1 with that camshaft size you might not want to go much past that, if you give up ignition timing compression you loose power. Im not the most knowledgeable on the dynamic compression ratio, but with aluminum heads youd want to stay under 8.2 to one, 8 to 1 would be a safe bet. If your changing pistons, what else do you plan on doing to the bottom end, bore, deck ect, this all comes into the dynamic also. Pat kelly and wallace racing both have good free to use compression static and dynamic calculators. Spend time there and figure out some of the things needed to be known before machine shop time and piston selection.

 

Edelebrock heads are aluminum

with a 64cc chamber doubt you have a true 10:1 dont worry about pinging. Your pistons could be 020 to 030 in the hole. With a "0" or .005 in the hole you may have 10ish depending on the piston/gasket used

 

Ok so after a little reasearch it says that the estreet heads have helicoiled stud bosses. So did edlebrock say why the studs would need to be changed? The machine work associated with the heads would be to accomodate the larger od spring. You could call edlebrock back and see if the sell a spring for that head to accomodate the camshaft you bought and if they do would you still have to change the studs? The article read was saying that it was somewhat costly to enlarge spring pockets.