Corvette project car

[FlatBlackCaddy]

Are you going to do anything to the bottom end? Have you done a compression check on this motor?

[hotrodalex]

Don't listen to them. Supercharge it or scrap it.

[280Z Turbo]

New heads and cam is part of the rebuild, no matter what. I know the seals are all no good.

[FlatBlackCaddy]

What's the stock compression on these?

[280Z Turbo]

What's the stock compression on these?

Probably about 10.5:1 or something

[FlatBlackCaddy]

Really, I didn't think it was that high.

A cam and a good set of heads, I would think, should be good for 350-375hp.

[280Z Turbo]

Really, I didn't think it was that high.

A cam and a good set of heads, I would think, should be good for 350-375hp.

Designed for high octane 1960s gas, mang.

This engine was tuned for a grocery getter with a Powerglide, so I think there's room for improvement.

[GoCougs]

I'm thinking these should wake the ol' motor up:

http://www.summitracing.com/parts/sum-152123

http://www.summitracing.com/parts/sum-k1103

With that relatively mild cam and stock/low(er) compression you're probably better off with 1.88/1.50 heads. Also, if compression is low/bad bigger cam/heads will just make things worse - bottom end power will die. Since that motor already has 1.88/1.50 heads you're better off with the stock heads if there's nothing wrong.

If compression is good and since you've gone through the distributor and carb I'd look next to a bad cam. Flat tappet cams go bad relatively quick (lobes wear and then get wiped) which absolutely kills performance. Simply pull a valve cover and mic the lift via the movement of the valve (divided of course by the rocker ratio). If lift is any measurable amount less than the spec replace it. I've replaced worn cams on few engines (stock for stock) and the difference is like a new engine.

[Secret Chimp]

You've gotta have bad compression or something. If a 327 with 4.11s feel pokey when my 318 with 2.93s and the mildest aftermarket cam on the planet feels fun, something in the basic squeezy-bangness isn't working well.

[280Z Turbo]

Yeah, with a high compression 327 with headers, 750 cfm carb, electronic ignition, 4.11 positraction rear with only 3000 lbs to haul around should roast the rear tires...but it really couldn't do it!

This motor needs help.

[280Z Turbo]

Also, I must say it rides really nicely with a new rear spring and KYB monotube shocks.

MrH's stuff must be overpriced because these are half the cost!

[280Z Turbo]

I apologize for my dad's featherlite foot.

1963 Corvette running

Ended up fixing the first gear engagement issue by adding washers under the transmission mount to make clearance for the underside of the short throw Hurst shifter. The levers were hitting the crossmember. Now it gets all 4 gears perfectly. No grinding or popping out anymore. The torque lock sliders solved the issue. A cheap fix for only $30 a piece.

[280Z Turbo]

Thinking about the frame issues. I'm not sure if it can be repaired. I can have a new one made from scratch for like $5000.

It's bent in the front and rusty in the rear.

[FoMoJo]

Thinking about the frame issues. I'm not sure if it can be repaired. I can have a new one made from scratch for like $5000.

It's bent in the front and rusty in the rear.

Sounds like a good investment.

[280Z Turbo]

Sounds like a good investment.

Yeah, the car has belonged to my dad since 1978. It's not really an investment, but it might be worthwhile given that the car is unlikely to go anywhere.

The frame issues cause a lot of other issues, so I feel it needs to be resolved for us to continue driving it without damaging the body.

[hotrodalex]

When I swapped engines we had a fun time getting the transmission crossmember back into place. A couple of years later, took it to a frame shop and got it straightened. When I did the clutch a couple of weeks ago, trans crossmember went back in like a Lego block. So apparently the frame shop did a good job.

[280Z Turbo]

Oh well ain't that fancy. It's removable! Must be nice!

This frame has complex issues that I don't quite understand the full extent of yet.

The passenger side wheel is further in than the drivers side wheel. Why? I don't know.

[280Z Turbo]

Is a solid lifter cam worth the headaches?

I kind of want to duplicate the 365 hp L76 motor using the 30-30 cam.

[Soup DeVille]

Is a solid lifter cam worth the headaches?

I kind of want to duplicate the 365 hp L76 motor using the 30-30 cam.

For you, who I assume knows to do he adjustments on time, and for a car drive. But occasionally?

Sure, why not?

[280Z Turbo]

It might be kinda gutless below 4000 rpm. Right now, the power peak is about 4800.

Supposedly those L76s would pull hard up to 7000 rpm. The tach doesn't go any higher than that.

I'm wondering if a more modern cam profile could retain the top end power with more low end.

[GoCougs]

Pass on the solid lifter cam - pretty much no benefit these days for a street machine and there will be major drawbacks (low vacuum, gutless at lower RPM), plus the L76 cam is meant for 11:1 CR which you're not going to be able to run. Cam grind tech has come light years since then. Plus, pretty much most everyone chooses too big a cam.

Anything more than a moderate grind like the Edelbrock Performer RPM on a 327 and you're looking at driveability and vacuum issues (and you might have vacuum issues even). The pinnacle of cam tech is a hydraulic roller but that will get pricy and you'll probably want a shop to do the build.

All in all your best bang for your buck will be a bored/stroked 383 with an Edelbrock Performer RPM and 2.02/1.60 heads (more displacement makes a cam run smaller) and a 9:1 CR. That will provide a lot of smooth usable power that a L76 clone couldn't even dream of providing.

[280Z Turbo]

What do I need vacuum for? I don't have any vacuum accessories.

I'll likely go with Summit Racing assembled cast iron heads and an 1105 hydraulic cam. I think the 1103 is unnecessarily mild.

It's got a 4:11 rear, so it's never lugging around anyway. The current cam is way too mild for that rear gear.

[hotrodalex]

No vacuum advance on the distributor?

[280Z Turbo]

There is, but that may not be correct for a hotter motor anyway.

[GoCougs]

What do I need vacuum for? I don't have any vacuum accessories.

I'll likely go with Summit Racing assembled cast iron heads and an 1105 hydraulic cam. I think the 1103 is unnecessarily mild.

It's got a 4:11 rear, so it's never lugging around anyway. The current cam is way too mild for that rear gear.

Some old hot rodder long ago said ALWAYS choose the smaller cam , and he's right, having been there a few times. It is possible to over cam an engine even with 4.11:1 gears. Unless you take advantage of the cam as it gets bigger it will actually make the car less usable and slower. I've been out of the scene for forever but the 1105 is sorta a big cam for a small small block. If you go stock otherwise - manifolds, dual plane intake, 1.88/1.50 heads, spread bore carb - it won't do much for you, and maybe even hurt a bit. If you go 1105 IMO you should plan on at least headers, Performer RPM intake, and Holley square bore carb.

[280Z Turbo]

How is a square bore carb better than a spread bore carb? It's 750 cfm.

It already has full length headers.

[Secret Chimp]

How is a square bore carb better than a spread bore carb? It's 750 cfm.

It already has full length headers.

They're set up to have smaller than normal primaries for good economy, made up for by the bigass secondaries. I think I might need to limit the secondaries on mine (it feels stronger at part throttle than WOT for most of the RPM range) but I can get 18 mpg and it doesn't have a hint of lean stumble at any time, unlike my old Carter that I couldn't jet down to anything better than 14.

That being said, I don't know if I could accomplish the same just as easily with a modern Holley, but the principle still works regardless.

[280Z Turbo]

Change the spring tension for opening the secondaries? I have a book on Quadrajunks.

[280Z Turbo]

Not sure how accurate it is, but kinda neat:

http://www.camquest.com/

[Soup DeVille]

Change the spring tension for opening the secondaries? I have a book on Quadrajunks.

More restriction in the vacuum pull-off