Please Help

[69ChevySB]

Hi there folks, I have a 1969 C-10 Shortbed Chevy with a 350 (or maybe it's a 327, how can I tell?), 3 speed on the floor, and I have a 6 bolt pattern on my wheels. I have a few questions if anyone would care to help:

1. How do I tell if my motor is a 327 or 350?

2. How do I tell what kind of rear end, or what gear ratio I have?

3. Why is my bolt pattern 6 bolts instead of 5 I thought 6 was only for 4 wheel drives, and mine is a C-10 (2 wheel drive). Does this have any affect on the performance of my truck? does it make it better worse?

4. When I am going down the freeway or highway my rpms are really high it seems like when I do 80-85 my rpms go way high like 4000+, is this not good and what should I do to prevent this? should I get a automatic transmission?


All help would be appreciated, Thanks!

[Mike C]

Welcome. On the front passengers side of your motor, stamped into the engine block deck behind the alternator, you will find a serial number as well as a two digit code (if the letter code is 3 digits, it is a 70 or later motor.) post that code and somebody can tell you what your motor is.
6 lug wheels were standard on the 1/2 ton trucks until 1970. In 1971 with the switch to disc brakes GM switched to 5 lug. It will not in any way hamper performance.
Most likely your truck has 3.73 gears. Because of the slippage of the torque converter, switching to a 3 speed auto will cause rpms to increase on the highway. I would consider a Th700 4 speed auto with overdrive.
I you don't like 4000+ rpm, just slow down. Speed limit is 70 MAX after all and your original drum brakes are marginal at best at 55 mph.

[ChevLoRay]

When these were new, even though freeway speed limits were about 75MPH, most people who drove them actually used them for work purposes, not transportation. People who used them for transportation only were usually thought to be weird.

Like said already, if you are driving 80-85MPH, you might think about slowing down. The chance that your engine will come unglued increases greatly, in direct proportion to the RPM's at which it is turning.

If you want to change to 5-lug wheels, check the board using the "Search" feature. There is usually something every week about someone wanting to change to discs, or 5-lugs, etc.

Welcome to the board. You will find a wealth of information of use to you, as well as an occasional comment that may be interpreted as sarcastic, or bombastic, or even an outright prevarication! We all mean well, and we all try to help. We like to have fun, too.

[69ChevySB]

Thanks for all the help guys, but also...how do I tell if my motor is a 327 or 350 and how do I tell what gears I have? sorry to be a pest if I seem to ask the same questions, but i'm not too familiar with everything involved in owning a truck, but i'd love to learn about it all. So just bear with me while I do

[bigjimzlll]

being its a small block, the 2 choices were 307 or 350 in 69..I have heard rumors the 327 was available, i have never seen one though..you will need to get the numbers off the block..as stated earlier..also there will be numbers by the bell housing, but the best ones are on the little pad on the passenger side in front of the head..clean it with some carb cleaner and give us the numbers..is it a 2 barrel or 4 barrel? a 4 barrel would be a 350 most likely
Jim

[GMCPaul]

If its a original 69 rearend you will find to letters stamped in the axle tube on the passenger side top front near the pumpkin, post these 2 letters and will tell you the original gear ratio, to determine the motor look on the passenger side of motor at the front base of the passenger side head and you will see a small pad of metal sticking out about 1/2" from block and about 1" long, stamped on this pad is the engine suffix, it will be a letter followed by 2-3 numbers followed by 1-3 letters, post this suffix and will tell you from it Plant it was assembled, month and day assembled, and what motor size is and what vehicle it started its life in.
GMCPaul