My 365 That Isn't

[George C.]

I have a 65 Convertible which I have owned for about 10 years. When I bought the car I got the "motor was rebuilt about 5,000 miles ago" with no specific information available. The good news is that it was indeed rebuilt, bored and has 30 over pistons in it, but they are flat top. And I have no real way to know what the Camshaft is either.
The good news is it was rebuilt, and not very long ago. I can still see the hone marks in the walls, and there is no ridge at the top of the cylinders.

I pulled the heads off it yesterday for a couple of reasons:
1. I have a #6 exhaust valve with a mushroomed stem that needs to be fixed.
2. I wanted to replace the press in studs with screw in type studs. I have a couple that are pulling slightly.
3. I wanted to see if I have a multi-angle valve grind, as per many discussion board posts this would improve low end torque on the 365 HP, and if not get one done.
My questions now are:
1. Will a multi-angle valve job still improve low end power now that I know I have a motor with flat top pistons in it?
2. I have a restored 380 FI unit that I want to put on the car and play with. I am not getting rid of the 365 carb and intake, just want to play with the FI, that I have been collecting parts for and had restored about 5 years ago.

Thank you all in advance,
George 36908

[Domenic T.]

Re: My 365 That Isn't

George,

Some guys are anal about the glue slop around the doors, overspray, orange peel etc. but when it comes to the engine they modify the very heart of the car by lowering the compression so they can use the lesser fuels available today.

When it was rebuilt they may have lowered the compression. I would check the valve spring pressure and see if they increased it as that may be your stud & mushroom problem.

I would look at the block #s to verify what you have.

I always do 3 angle seats and sometimes a 2 angle on the valve to get the extra edge but the 3 angle on the seats keeps the seat the same width all the way around for good sealing & even cooling of the valve.

DOM

[Hal E.]

Re: My 365 That Isn't

As I recall the 365 has a solid lifter cam with unique requirements for timing and valve adjustment procedures. I believe that it is the only SBC where the valves have to be adjusted using this procedure. It is probably outlined in the Chevrolet Service Manual for 65. Believe the OEM pistons were a NOMINAL 11:1 compression like the 327/340....but it actually may have been a little lower when it left the factory.....like 10.5:1

[Clem Z.]

Re: My 365 That Isn't

3 angle valve job and back cut the valves will help bottom end HP. http://www.google.com/search?q=back+...w=1164&bih=566 also from the machine marks on the block the block has been decked so i would CC the head chambers and check the deck height to see what compression ratio you have

[Timothy B.]

Re: My 365 That Isn't

George,

If it's the original motor for your car why not take the block out and overhaul it back the it's original state. Get the correct pistons and check the deck height to make sure you get that compression back where it should be and install the 365hp camshaft. The block will probably only need a hone but go to a good machine shop and make sure they understand about the #'s on the block pad, (get it in writing).

[George C.]

Re: My 365 That Isn't

Hi guys, and thanks for the responses. One of the questions I asked was about the block stamping. What is the opinion of the experts, original or restamped? More to follow after supper, I just got back from the machine shop.
Thank you,
George

[Duke W.]

Re: My 365 That Isn't

"I wanted to see if I have a multi-angle valve grind, as per many discussion board posts this would improve low end torque on the 365 HP, and if not get one done."

...never seen that claim, before. Multiangle valve jobs primarily improve low lift flow and the biggest benefit of flow improvement measures is in the upper third of the rev range.

Low end power improvment is a matter of valve timing - less overlap and an earlier closing inlet valve are the only way to improve low end in any meaningful matter. High overlap and low compression is the worst possible combination for low end power.

The 30-30 cam is utterly hopeless for low end torque regardless of what you do with the heads, valves, or spark advance map. It's just way too big a cam for road use, but it's a good vintage racing cam with headers and open exhaust.

Duke

[George C.]

Re: My 365 That Isn't

Duke,
Thanks for responding I was looking for your input. I really thought I had read on the board here that a multi-angle valve job would improve the low end power, guess I need to go back and re-read and see how I misunderstood.
So with flat top pistons and assuming I have the 30-30 cam still in it, I guess I am still without any low end power. I haven't figured out what to do about the pistons, I guess I should be happy it runs pretty well on pump gas and is lumpy at idle and fun to put the pedal down. But I am researching options to bump the compression back up and keep it able to run on todays fuel.
Any input on my block stamping? I think the numbers look like other postings that have been verified, but don't know about the broach marks. I did use some 220 sand paper to get the paint off when I first bought the car 10-12 years ago. Do you think I damaged the broach marks with sand paper? Any thoughts on more cleaning, brass brush and carb cleaner?

Thank you,
George

[Clem Z.]

Re: My 365 That Isn't

the back cut on the valve allows a better flow at the lower lift just as the valve starts to open. more flow sooner at lower lift as the port has more area open for the same lift.

[Clem Z.]

Re: My 365 That Isn't

Duke,
Thanks for responding I was looking for your input. I really thought I had read on the board here that a multi-angle valve job would improve the low end power, guess I need to go back and re-read and see how I misunderstood.
So with flat top pistons and assuming I have the 30-30 cam still in it, I guess I am still without any low end power. I haven't figured out what to do about the pistons, I guess I should be happy it runs pretty well on pump gas and is lumpy at idle and fun to put the pedal down. But I am researching options to bump the compression back up and keep it able to run on todays fuel.
Any input on my block stamping? I think the numbers look like other postings that have been verified, but don't know about the broach marks. I did use some 220 sand paper to get the paint off when I first bought the car 10-12 years ago. Do you think I damaged the broach marks with sand paper? Any thoughts on more cleaning, brass brush and carb cleaner?

Thank you,
George

those angled marks at the top of the picture looks like what you see when you deck a block with a rotary cutter. clean the the rest of the deck with lacquer thinner and see if those marks are any place on the deck

[George C.]

Re: My 365 That Isn't

To all,
I took the heads to a local shop recommended by some friends and neighbors. We pulled out a couple valves and it looks like the last valve job was a long time ago, maybe even 1965 when it was built. The guides are worn and will be replaced, all valves changed to Stainless Steel, new springs retainers and keepers. He will also machine and install the screw in studs. He is going to magnaflux the heads, I believe they are fine, but it's that insurance thing.
I let him talk me into hardened seats, he swears it is the right thing to do, and the cost for the seats, machining & install was $80.00. I have read on this board where it isn't needed and is wasted money. Also ready the dangers about boring into the water jacket. This guy stated he uses small seats and that he feels it is safe and really needed for longevity.
He works on everything from current race cars to vintage stuff, was building a set of old 426 Hemi heads when I got there. Even saw some rice rocket stuff being done. So I think I have them at a good place.
Still looking for input on my stamp pad and casting date. The casting date in the heads were both C 245. I belive that is March 24 65?

Thank you all,
George

[George C.]

Re: My 365 That Isn't

those angled marks at the top of the picture looks like what you see when you deck a block with a rotary cutter. clean the the rest of the deck with lacquer thinner and see if those marks are any place on the deck

Clem,
I wondered about those marks myself, I used to work in a machine tool shop many years ago. I didn't even see those marks until I looked at the pictures. I'll try to clean it up some more and get some better shots.
Thanks again,
George

[Tom D.]

Re: My 365 That Isn't

George: You are reading the casting dates correctly.

[John M.]

Re: My 365 That Isn't

George,
Regarding the pad. Can you clean up the area and take a couple more clear closeups? Maybe then you can get some good opinions.
It looks as if the block was machined but they stayed away from the pad but it's hard to tell from that picture. If you work the block make sure he stays away from that area, it's not hard to do.

[Duke W.]

Re: My 365 That Isn't

Stamp pads are difficult to evaluate with photos, and your photo is at a "bad" angle. When judging the pad is observed from different angles with different lighting for a full evaluation. In general only paint remover should be used on pads, and, maybe, a derusting agent. Any type of abrasive should be avoided, period.

As long as the heads are off you can take steps to maximize compression. Dig out your Fall 2009 Corvette Restorer.

Did you check the lifters to determine if they are mechanical or hydraulic? With the manifold off you can easily measure lobe lift with a dial indicator, which will likely give a very good clue as to the installed cam.

If there is no significant seat erosion, why does it need hardened seats? You're better off spending the money on head massaging. Dig out your Fall 2010 Corvette Restorer.

All stainless steel valves are a waste of funds that can be put to better use elsewhere, like massaging heads. OE replacement valves are fine. 21-2N stainless on the exhaust side is a reasonable upgrade, but a waste of money on the inlet side. The NAPA online catalog has all the choices from Fedearal Mogul.

If you don't know what cam it has, how do you know the valve spring requirement. What valvesprings were removed? OE? If aftermarket what is the nominal seat force the rate?

What technology valve guides and seals are being used? If you can explain it to us, that means you understand it.

You're letting the "engine builder" call the shots. I certainly don't agree with everything he is proposing, but you have not provided us with any real technical specifications, so it it tough to evalute, like whether the new valve springs are matched to the cam lobe dynamics. You're the customer who is paying the bill. Get educated and manage your project. If he won't do what you want, find another shop.

Duke