365hp 327 on 93 pump gas ok?

[Mycarispurty]

I'm pretty sure the valve seats have been changed before since it was a running motor a year ago. I still don't know if I'm going to get it. Even if we get it running, parts of me want to run it as is with a different cam so it'd be a bit 93 octane friendlier. Then part of me wants to just put like some Speed Pro forged flat tops in to bring the compression down a little since I'll probably take most of it apart to change out bearings and seals/gaskets.

 

I guess it depends on what it looks like when we pull it and I yank the oil pan and valve covers to see how the internals look.

[johnc]

As others are posting, if its a real 327/365hp block and head combination its worth a lot of money to the Corvette guys. Check the block and head numbers to verify and hopefully the block has never been decked. The original broaching lines on the serial number pad add something to the value of the engine.

 

I'm not an expert but I think the engine serial number should have either an "F" or "T" after the seven digit serial number followed by "HK", "HL", "HM", or "RE" if its a 327/365.

[dr_hunt]

IMO the hardened seat issue is really a non issue and nothing but a bunch of hype. The lead was a guide and stem lubricant not a seat lube. I have never seen any issues using old heads without hardened seats with todays gas.

[Mike C]

I have a 327 in my Jimmy. Actually, a 331 now. It is a full point lower than the motor you are discussing, but basically the same heads. A 186 on one side and an 041 on the other. Both have non-hardened seats. It's not the first set of heads I've had on the 100k mile motor, but I had a bronze guide fail in the first set and it allowed the valve to wallow around enough that the seat could not be cut back far enough for an insert before it hit water. The rest of the seats were fine using springs with about 80# on the seat. BUT, the second set of heads has at least 50k miles on them with no additives running cheap gas at 5000# of weight, with quite a few of those miles pulling a 4000# boat and trailer along with 35" tires. I would not hesitate to run an 11:1 motor with good gas in a light car. Just be careful with mixture, total timing and spark curve. Reduce weight, add gear, or increase overlap on cam will all help with spark knock as well. A good set of composite head gaskets instead of the OEM gasket wouldn't hurt either.

[waynekarnes]

though it's been parked in the garage and has not moved under its own power since 1986, my '58 vette has a 365/327.

 

i bought car when i was a senior in high school, 1974.

 

it belonged to my uncle's best friend. he had time slips from bayland/fremont raceway showing 10.8 seconds for the quarter mile.

 

i know for a fact would easily pull both front tires 10 inches off the ground, keep tires in the air through 3rd gear. i had to do the body work to fix the fiberglas behind the rear wheels after i proved to neighbor could pull the wheels.

 

as far as the 93 octane, if you kept the temps down and the timing correct, you should be able to run the 365/ 327 on the pump gas. i would consider adding a real octane booster on the weekends or anytime you were planning on some horse play.

 

i had a 70 LT-1 roadster in 1981. 370/350. person i bought from had shaved the heads and other stupid stuff. was running 12 to 1 compression.

 

as long as i did not stand on it, was able to run on the unleaded premium.

 

if i eased into it, could get some speed and no issues.

 

if stood on it, forget it, massive detonation. once blew the electrode out of 2 of the yellow accel racing plugs. spark plug wire was laying up on the inner fender well.

 

detonation issues are also different with an auto trans vs. a manual.

 

driving style also affects detonation.

 

i have friends with hot rod chevys running 11 to 1 compression, couple use em as daily drivers.

 

as long as they don't go wide open throttle, they have no problems.

 

when they want to have a little fun, they add octane booster.

 

if you want a 327 in your z and, that is a real 365/327, you oughta see if you can pick it up.

 

i think you will be happy with it.

 

there are several things you can do to eliminate detonation.

 

popular back when was water/alcohol injection.

 

wayne

[pparaska]

The cam in the 327/365 has so much seat duration and overlap that it's not running as much dynamic compression as you think it would be, even with 11:1 static compression. It's hard to really know what the spec were of the old 346 (bigger Duntov 30-30 cam) were in terms of .006" or .050" lift - but there were very long ramps on that cam that allowed lots of compression to escape. I'm betting that if it is an all-original 327/365 it's worth a good bit and if in good condition would be fine on 93 octane. Personally, i'd put a modern design cam in it - it will make more power and be easier to drive.

[waynekarnes]

hi Pete !

 

our 2200 deal still on, is it not ? wink wink.

 

you are correct about that duntov 30-30 cam.

 

also correct that changing it out to a modern design will bring more horsepower.

 

plus, change over to hydraulic, get more torque and hp without having to adjust the lifters every 4000 to 5000 miles.

 

though, is hard to beat the sound of the tick tick and the lump lump at idle.

[Guest BurdGuy]

I'd verify the block and head numbers then pull the heads and cc the chanbers if the numbers don't match up. IF it is in fact a 365/327, then buy it no matter what. You could play it safe and pull the heads and have them rebuilt with nice bronze guides and harder seats.

 

327s are a much more fun engine to drive, compared to a 350.

 

The 750 seems a little big to me, but if it is a vacuum secondary unit it would be alright. At worst, you may lose a little throttle response and fuel economy. If you have the money, call one of the better carburetor shops and have a Q-Jet set up for that thing. Cost is just slightly more than a new Holley. I rode in a Chevelle with a Q-Jet set up by Cliff Ruggles and that thing freakin screamed! I was surprised at the crisp throttle response and fuel economy it was getting.

 

As for running a 11:1 or higher engine on unleaded gas, I guess I'm personally leary of that. I'd agree a cam with a longer duration and more overlap would bleed off a lot of the compression, but the line is so fine between the good and bad side of detonation when you are tuning it. You may want to consider a roller cam. The lobe ramps and valve events are much more radical than a flat tappet's and they are designed for high compression aluminum headed engines.

 

There can be detonation going on that is not heard. Pre-detonation is death to rod and main bearings. If you're really comfortable with tuning it for unleaded gas, go for it.

[Pyro]

I'd verify the block and head numbers then pull the heads and cc the chanbers if the numbers don't match up. IF it is in fact a 365/327, then buy it no matter what. You could play it safe and pull the heads and have them rebuilt with nice bronze guides and harder seats.

 

327s are a much more fun engine to drive, compared to a 350.

 

The 750 seems a little big to me, but if it is a vacuum secondary unit it would be alright. At worst, you may lose a little throttle response and fuel economy. If you have the money, call one of the better carburetor shops and have a Q-Jet set up for that thing. Cost is just slightly more than a new Holley. I rode in a Chevelle with a Q-Jet set up by Cliff Ruggles and that thing freakin screamed! I was surprised at the crisp throttle response and fuel economy it was getting.

 

As for running a 11:1 or higher engine on unleaded gas, I guess I'm personally leary of that. I'd agree a cam with a longer duration and more overlap would bleed off a lot of the compression, but the line is so fine between the good and bad side of detonation when you are tuning it. You may want to consider a roller cam. The lobe ramps and valve events are much more radical than a flat tappet's and they are designed for high compression aluminum headed engines.

 

There can be detonation going on that is not heard. Pre-detonation is death to rod and main bearings. If you're really comfortable with tuning it for unleaded gas, go for it.

 

Why would you consider a 327 more fun to drive? less torque is more fun? my 350 spins up to 7200. it's the cam that makes revs not the stroke when comparing a 327 to a 350.

 

A cliff q-jet is very good. but cost 500.00 and will take 6 months to get. I have called cliff and asked. A 3310 750 holley is 1/2 the price and can be had in a few days.

 

overlap doesn't bleed off compression. the engine isn't even trying to make compression on that part of the cycle. A longer duration cam with a later closing intake valve is what bleeds cylinder pressure.

 

11:1 isn't a problem with a 292H compcam. I full full timing in my 11;1 350 with 93 octane without any issues. (3.90 gear and T5 trans)

 

Roller have quicker ramps so a cam with the same at 0.050" numbers will have less advertised duration which makes more cylinder pressure as compared to a flat tappet cam. so, rollers work better with less compression, not more.

[dr_hunt]

I'd verify the block and head numbers then pull the heads and cc the chanbers if the numbers don't match up. IF it is in fact a 365/327, then buy it no matter what. You could play it safe and pull the heads and have them rebuilt with nice bronze guides and harder seats.

 

No need to pull the heads and cc the chambers as the casting numbers are inside the valve cover. At worst case that is all you need to do and be spot on as to what heads are on that engine.