1969 427/327 corvette stingray
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Heel & Toe
Joined: Jul 2022
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1969 427/327 corvette stingray
Guys, I’m looking for advice here please, about 30 years ago I bought a 1969 corvette 427/390 hp 4 speed non matching numbers car. The 427 was shot so I pulled it an put in a 327/350hp. The car runs really well. I rebuilt the 427 last year again it’s NOT numbers matching. It’s going to be some work to get it in there I’m just wondering if it’s worth the effort. As I said the 327 runs great ! But the car is an original 427/390 car I don’t have the matching numbers engine and that’s not a big deal to me. Advice???
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I think it would be worth the effort. I have always liked my BB chevy motors. The low end torque is amazing.
Melting Slicks
Joined: Nov 2006
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From: Apple Valley, MN
1968 was the last year for the 327 in the Corvette. Generally speaking, a non-standard engine will diminish the value of any car.
You say the 427 is non-matching numbers but what does that entail - just the right front pad stampings? What about the block casting number and date code? Same question for the heads, intake and exhaust manifolds and water pump.
What about the starter, carb, fan clutch numbers?
If you have a period Corvette correct 427, that is the next best thing. If it is a mishmash of random parts, some that may not have ever been installed in any production Corvette, it may not be worth the time and effort to swap it out.
The other big question is what shape is the rest of the car in? Frame? Birdcage? If the car is a mutt, then I wouldn’t put forth any effort to swap it. In the other hand, if it’s a nice car, then maybe another story.
You say the 427 is non-matching numbers but what does that entail - just the right front pad stampings? What about the block casting number and date code? Same question for the heads, intake and exhaust manifolds and water pump.
What about the starter, carb, fan clutch numbers?
If you have a period Corvette correct 427, that is the next best thing. If it is a mishmash of random parts, some that may not have ever been installed in any production Corvette, it may not be worth the time and effort to swap it out.
The other big question is what shape is the rest of the car in? Frame? Birdcage? If the car is a mutt, then I wouldn’t put forth any effort to swap it. In the other hand, if it’s a nice car, then maybe another story.
Last edited by 69L88; Jul 31, 2022 at 09:37 AM.
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From: Sunshine Coast, Queensland, Australia
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And, The big block will almost definitely make more torque,
And that is fun!
Cons, weighs more, affecting handling, to what degree? Lots of different opinions.
Sucks a TON more fuel. But gasoline is cheap!
Big block cars generally bring more when time to sell.
Are you selling or driving.
Big torque, or better fuel economy, Not that even the 327 will match a modern Honda. But there is a difference and fuel is so inexpensive these days.
Your car, your call.
And that is fun!
Cons, weighs more, affecting handling, to what degree? Lots of different opinions.
Sucks a TON more fuel. But gasoline is cheap!
Big block cars generally bring more when time to sell.
Are you selling or driving.
Big torque, or better fuel economy, Not that even the 327 will match a modern Honda. But there is a difference and fuel is so inexpensive these days.
Your car, your call.
Le Mans Master
Joined: Aug 2005
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From: Temple Terrace Florida
Since the car is no longer numbers matching, consider using your 427 short block and replacing the iron heads with new aluminum heads. The weight savings will help with handling. Jerry
Is my vette stock?? HAHA
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I did the reverse. Love the big block. Power, sound, attitude. Its awesome. I went from 16 mpg to 12 mpg. I have adjustable springs in the front so i stiffened them up and there is zero difference in handling. If you left the big block springs in then theres no big deal to go back.
The single biggest difference is tire selection. I went from a high performance summer 235/55/17 back to 255/60/15 and 275/60/15. The rear feels a little loose at 80mph playing with the tuner kids but ive only had them at that speed a few times. And it will howl at Low speeds on the really sharp turns. I could put more camber in the rear to get more grip if i really wanted to race
You should consider a 5 speed if you are in the car long term. You can go with a lower ratio for the low end grunt and make up for it with 5th gear on yhe highway. I have a .64 overdrive and 75 mph is 2600 rpm, 80 is 2700 rpm if i remember correctly
The single biggest difference is tire selection. I went from a high performance summer 235/55/17 back to 255/60/15 and 275/60/15. The rear feels a little loose at 80mph playing with the tuner kids but ive only had them at that speed a few times. And it will howl at Low speeds on the really sharp turns. I could put more camber in the rear to get more grip if i really wanted to race
You should consider a 5 speed if you are in the car long term. You can go with a lower ratio for the low end grunt and make up for it with 5th gear on yhe highway. I have a .64 overdrive and 75 mph is 2600 rpm, 80 is 2700 rpm if i remember correctly
Team Owner
Joined: Apr 1999
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From: Reno Nevada
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The 390 HP is a real turd of a motor. In the non or mildly modified class at the all corvette drag races the higher HP 327 and 350's beat the big heavy 427 390. The weight difference makes the 390 a big looser and they don't have TQ or get up and go. I've driven them. When you sell the car consider installing or offer the motor along with the deal
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From: Napa Valley California
You stated in post #1 that you rebuilt the 427.
What did you put into it?
Is it basically stock or did you put some goodies into it?
I love big blocks and my 73 has the numbers matching 454, which is coming out soon and being replaced with a 496 putting out 600+ hp.
The TH 400 is getting replaced with a 5 spd.
It will be non numbers matching, but I don’t care, I want it to be fun to drive, the gas mileage will be poor, and it will be fun to drive!
Did I say it will be fun to drive?
The oem drive train was designed to take about 450-500 hp max and anything over that and you’ll find yourself upgrading everything, which is beyond expensive.
If I had to do it again I would stay under 500 hp, save a ton of money and would probably still have a car that was fun to drive.
Your choice, but I would put that fresh 427 back in and have some fun.
You won’t hurt the value and there are plenty of buyers, like me, who only want a Corvette if it’s a big block.
Show us some pictures, please.
What did you put into it?
Is it basically stock or did you put some goodies into it?
I love big blocks and my 73 has the numbers matching 454, which is coming out soon and being replaced with a 496 putting out 600+ hp.
The TH 400 is getting replaced with a 5 spd.
It will be non numbers matching, but I don’t care, I want it to be fun to drive, the gas mileage will be poor, and it will be fun to drive!
Did I say it will be fun to drive?
The oem drive train was designed to take about 450-500 hp max and anything over that and you’ll find yourself upgrading everything, which is beyond expensive.
If I had to do it again I would stay under 500 hp, save a ton of money and would probably still have a car that was fun to drive.
Your choice, but I would put that fresh 427 back in and have some fun.
You won’t hurt the value and there are plenty of buyers, like me, who only want a Corvette if it’s a big block.
Show us some pictures, please.
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Is my vette stock?? HAHA
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all it needs is heads, a cam and headers and it will run. it should have 10.25:1 and with a smaller chamber you could bump it up a point. But you have to check clearances due to dome shape
Last edited by Rescue Rogers; Jul 31, 2022 at 04:20 PM.
Thread Starter
Heel & Toe
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This is what I did. They say by running aluminum heads, intake, water pump, you can reduce the weight of the big block considerably. So weight shouldn’t be a problem. 427 is a 1968 and block casting is not correct for the car.
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Heel & Toe
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Thanks for all your replies. The car is in decent shape, over the last 30 years I think I’ve replaced most things. I do love the way big blocks pull. My 70 chevelle 396 is awesome. I’m running a better cam than stock, engine has 11/1 TRW pistons and I went with aluminum heads with 119 cc chambers, oval port which should drop my compression to 10/1. Rear gears are 336 so I’m probably good there. I guess if it doesn’t work out I’ll just put the small block back in. I’ll try to post some pictures if I can figure it out.