Just bought a 71 small block, auto transmission, well optioned with everything working including the factory A/C. Runs like a scalded dog-----instant pedal response at all speeds and smooth almost un-noticeable shifting. Interior is complete and in very good condition. 66K original miles. Price was $11.5K which I thought was good.

I appreciate your patience with and input on a few questions:

1. Regular gas OK, or do I need a higher octane?

2. What type/weight oil?

3. How exactly do I tell if it is a matching numbers car? I was told that it is.

4. On initial startup I stood directly behind the vehicle and saw no smoke whatsoever. After about a 15 minute run, I stopped the vehicle and re-started after a few minutes and there was a good puff of black smoke. Is this normal on a quick restart when warm or is it a carb adjustment issue? No smoke whatsoever when running, even on acceleration.

5. Also, it starts right up when cold, when warm however, it lags a bit as if the battery has run down, but still starts right up.

6. Finally, when warmed up after stopping, a shift into reverse produces a noticible clunk coming from the rear end. Does not do this on initial startup when cold, or when shifting into Drive from Park.

I know these are quite a few questions, but I would really appreciate your input. No better place to seek guidance that a group like this. Thanks in advance for your input.

 

A lot of your questions are subject to opinion, but let me state mine on a few;

#1. I'd run regular and listen carefully for detonation. If it will run fine on regular, use it.

#2. Too many opinions out there. I run el-cheapo oil in ALL my cars, but run good filters. I've never had an engine failure in 30 years of hard driving.

#3. Beter left to the NCRS guys. LOTS of numbers from alternator, A.C. pump, engine, etc. to check.

#4. Not uncommon, but not NORMAL. Won't hurt anything, but probably fuel boiling into the manifold, or just too many cranks richening things up before firing. Or...

#5. Hot soak starter problems are the bane of G.M. V-8's.

#6. ???

 

#6 could be a bad ujoint. Might be in the rear end but the ujoints are usually the problem on clunks in the rear.

 

6 - Differential mount

 

#6 Another cause offten overlooked is the front bushing on the differential. Easy to check, have someone shift the car back and forth from drive to reverse while you look at the front of the diff from the side of the car, for safetys sake, don't put your head under the car. If it is bad, you can see it jump up or down, it is a 2 part top and bottom rubber bushing with a thru bolt.

 

That's the usual suspect. It's also not uncommon for the bracket itself to be loose. Check the two through-bolts on the bracket to make sure it's tight.

The black smoke is probably leaking well plugs in the carb.

The slower cranking on a hot start is probably a tired starter/solenoid. Could also be corrosion in the cables.

 

Thanks for all the tips. Last project was a 61 Apache----this one looks to be a lot more fun. Any suggestions on a good repair manual?

 

Closest I could find for the Apache manual is here.

 

I am guessing he meant for a '71 vette, there are several out there. You will want a GM service manual for 1971 Chevrolets (includes Corvette) and an assembly manual which gives you a detailed drawing of most all parts and how they fit. Both sell for around $25-30, from any Corvette parts supplier. There are also several by different authors on restorations of corvettes, check the transportation section of a good bookseller like Borders.



PS here's a link to Corvette Central

http://www.corvettecentral.com/

Then click on circle at top for 68-82, the search by description Books etc and put in the year.

 

Thanks!

 

#1. Regular is OK. If pings on reg then probably some carbon buildup.
#2. You'll get lots of opinions on this but I prefer 10W40.
#3. Probably lots of parts have been replaced but an engine having the same VIN as the chasis is considered numbers matching by most.
#4. Black smoke is a rich condition and could be caused by lots of things. Most probably in your case is a sticking carb float or float needing adjustment. A little black is a lot better than white (water) or blue (oil).
#5. Corroded battery cables, excessive heat at the starter, or too much timing advance. Probably battery cables.
#6. Universal joints or tranny mounts.

Congrats on your purchase.