hockystik

I've been looking for a nice mid year driver. I found a 1966 with a 327/350 hp. A friend told me those had 11: 1 compression ratio and won't run on pump gas. Is this true and what do these run on and if the last owner ran on pump gas, what kind of damage could this have done? Am I better off finding a 327/300?
Thanks for any help.

Gary's '66

No, It's NOT true! My '66 327/350 runs great on pump gas. Your friend needs a 101 lesson on L-79 motors.

Geek's 65

What he said. Another "expert".

hockystik

So you guys run 91-93 octane in original L-79 motors with no problems? Is there a BIG power difference between the 300 and the 350 hp?

BlackbirdZ07

I've owned both. There is a difference, but it's not a big difference.

Gary's '66

Yep, and here in Ca. 91 octane is the highest available, period. The key to running these older motors on the now lower octane gasoline is proper tuning which, of course, will also produce the best performance. That's it in a nut shell.

BB767

I currently own cars with both versions of the 327, an L79 350hp and a base 300 hp car. For all around driving on the street my base 300 hp car is a real sweetheart. For typical street driving the difference between the two isn't all that great. Out on the drag strip though it's a different matter all together. Maybe if I was 25 years old again and running around with my hair on fire I'd feel different but I'm perfectly content driving the base car. The L79 is a great engine, maybe one of Chevrolet's best ever and in my experience if it's properly set up will run just fine on today's pump gas, no worries. Good luck to you.

Thomas

Larry21556

here in town I can get 100 octane at the pump. Does my 65 like it better, sure. is it 9.00 a gallon better, no. I run just fine on Costco 91 octane.

timmah22

My L-79 runs great on 93 octane. I was a little worried too with the ethanol and all. No worries. Just have that high revin' motor tuned right (timing, mixture, ect). I would recommend staying away from the cheap gas stations. And know what you have in your gas tank when the temps change. Winter blends are more prone to percolation on hot days. Most states change to summer blends in the beginning of June and to winter blends in mid September.

66since71

Add my voice .. My L79 runs just fine on pump premium. I've had both motors in my 66. The 300 HP motor makes good torque, but is all out of air by 5000. The 350 HP motor loves to rev, and for me at least, is more fun to drive. But I won lots of autocrosses with that 300 HP motor.

Harry

65hihp

A mechanic told me, my buddy said, a friend told me, some guy at a show came up and said that.......
welcome to the world of classic corvette ownership.

Absolutely everyone in the world is an expert on your car.

Assume everything you are told is false except one thing. Well two things.

One- If you have the hood up on a sunny day, have a towel laid onto your air cleaner lid to prevent cooking bubbles in your hood paint,

Two- if you don't drive your mid year frequently, bad things will happen.

hockystik

I’m listening to you guys. I’m feeling better about the 350 now. Anymore input welcome. Thanks to those that have responded.

toddalin

Mine was set up over 25 years ago for street use with 9.5:1 compression, hardened seats, etc. and I run it with 91 octane without a hint of detonation, regardless of the timing setting. I could probably run it on the 89 or 87 octane if I wanted, without detonation, knock, or dieseling.

Mine is a modified 300 hp engine and it is much quicker than it was as a 300, but there was much other work done (e.g., head work), so it is not totally a comparable situation.

BTW, everybody says these cams love to rev, and they do compared to the 300 hp engine, but the reality is that after 5,500 RPM, the valves float and they fall on their face and you get your best ets "short-shifting" the car.



331 CI, pump-friendly 9.5:1 CR
K&N 14"x4" air filter, Corvette drop base and lid
Holley 600 dp, choke horn milled and blended, Primary - 69, Secondary – 74, Squirters - 21
1/2" Aluminum open spacer port matched to manifold, exterior polished
Edelbrock Performer RPM intake manifold, port matched, exterior polished with all extraneous castings and lettering removed
Homemade lifter valley splash shield to keep hot oil off manifold bottom
Manifold heat riser crossover blocked
Camel hump 1.94/1.50 heads hogged out to 2.02/1.60, pocket ported, port matched, pump-friendly hardened seats, 3-angle valve job
Cylinder bores clearanced to unshroud the valves
Comp Cams 1.52:1 roller-tip rockers
Crane Cam Vintage Muscle 327/350 hp cam, 222 degrees @ 0.05, 0.447" lift (with 1.50 rockers)
Doug Thorley headers, dechromed and ceramic-coated
2.5" mandral-bent exhaust (including tips), 2" cross-over just before rear axle
DynoMax stainless Ultra Flow mufflers
Millerspeed 1-1/2” Gilmer under drive belt drive system
Mallory Hyfire IV CD ignition box triggered off Accel points
Mallory high voltage chrome coil
Mallory spiral-wound coil wire
Mallory solid copper plug wires, ends soldered to wires
Champion plugs
37 degrees total ignition advance
Carter high volume fuel pump
Melling high volume oil pump
Open breathers
Polished aluminum high flow water pump
160-degree thermostat
Flex fan with polished aluminum spacer
Polished aluminum one-wire 100 amp alternator
Header Power Bracket
Keisler TKO600 5-Speed
Hurst shifter
3.70:1 positraction with Big Block yokes
225/60/15 Firestone Firehawk SZ50s on 7”-wide Western 30-spoke

hockystik

One more thing to add. I usually “baby” my cars. I like to enjoy the power but hate to brake things that dig deep into my pocket. So, while I’d enjoy stepping on the gas, I won’t be racing it. Does my easy driving change anyone’s opinion on the 350 hp?

csysman

Base 300 HP great, had a few - L79 350 HP best engine ever stll have - also more desirable for resale
both run ok on 91 or higher
enjoy the car and I wouldnt worry so much about any engine damage------ more carb issues with the ethanol then engine issues from what Ive read

Easy Rhino

This very true - if you don't drive it and enjoy it often, your attitude and general disposition will suffer. That's a fact.

OP, full disclosure, I am more drawn to the L76 with solid lifters and higher revs and all, but consider the L79 quite possibly the best blend of performance and drivability of all '65/66 engine choices.

That's just my opinion, and it's worth every penny that you paid for it.

ricks327

I have owned my 67 L79 since 2001, no problems with regular pump gas. Did the Hot Rod Power Tour this year, 3000 miles in 9 days, it ran great.
Rick

Revette

I've owned my '66 L79 since 1968 and I notice a difference between the fuels of today and performance with fuels of 1968. I do get a bit of "ping" if I put my foot into it on 91 octane gas that is available today so I make an occasional stop at a local vendor that sells 110 octane leaded racing fuel. It seems like my '66 likes the "witches brew" of fuel that I run in it with a few gallons of 110 added to a tankful. The car starts much quicker/easier and the exhaust does have a different smell to it. My wife will come home and tell me, "you had the '66 running today, I can smell it in the garage".

Gary's '66

If your car is pinging you need to look into a few things to fix it other than a "witches brew" to solve your issue.

Donny Brass

mine will run just fine on 93...... with a little timing pulled out.