Cruising speeds

Mad4slalom

Mad4slalom

CCCUK Member
Hi , just wondering what to expect speed wise from a 48 year old vette, what do folk here find their 350 vettes are happy cruising at. Motorway speeds easy? Anyone pushed it beyond ? ( off public roads of course) mine has a frehly rebuilt motor with higher comp, cam etc but really dont know what to expect .
 
HJG

HJG

Well-known user
Whatever you feel comfortable with!
My big block feels happy at 60-70mph but it's more about how much noise yoi can deal with!
It's very car dependant. My 205GTi feels like it's at 20 000 rpm at 70mph whereas a McLaren feels like its idling at 70mph and C3 427 at 70+ feels like it has all the torque left in the world but the 4speed box makes it feel like it's about to blow up =D
 
Nassau65

Nassau65

CCCUK Member
I’m quite happy to drive C3’s at 70 on they way back from Southampton. My 65 is also happy at 70 but the noise with side exhausts is loud. Bought home a 1969 with side pipes from Southampton, my dad hated it. I think it gave him a headache. Side exhausts seem to drone in coupes, in Convertibles it seems different.
 
Chuffer

Chuffer

CCCUK regional rep
Mad4slalom said:
Hi , just wondering what to expect speed wise from a 48 year old vette, what do folk here find their 350 vettes are happy cruising at. Motorway speeds easy? Anyone pushed it beyond ? ( off public roads of course) mine has a frehly rebuilt motor with higher comp, cam etc but really dont know what to expect .
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Hi Mad4 , it will depend on a number of factors , the level of engine tune / mods , 3 speed auto or 4 speed manual , and ratio of the diff . My 1980 has a 305 cu. 9.5 : 1 compression engine from a 1985 Camaro IROC-Z with 4 Barrel 750cfm carb and Edelbrock Torker 2 manifold . It has a TH350 auto trans and standard 3.08 : 1 diff .
I have cruised for mile after mile on dual carriageways at the legal limit and a tad over , but it aint very relaxing and makes my ears bleed after an hour or two as it has no cat and straight through pipes . 50 to 60 mph makes for a more relaxed ride but just love cruzin at 40 to 50 on single carriageways and enjoying the ride :cool: Hope you can get out soon and do your thing (y)
 
Nassau65

Nassau65

CCCUK Member
With the volume of traffic on our motorways nowadays, I don’t usually exceed 70-75 mph in most American vehicles I drive. Not that they will not exceed that figure comfortably, but stopping them is the worry. 35+ years ago was a different matter, and quite often 80-85 on the M1 was done with ease. I think about 60mph is nice now. A few years ago on the way to Billing, I was doing 70, and a 1958 Impala Convertible wizzed past me like I was standing still. 5 up, and the top down. WOW, brave man.
 
Roscobbc

Roscobbc

Moderator
There are also cruising speed limits with the earlier C3's relating to potential cooling issues. My BB '68 4 speed with 3.08 rear end was/is happy to cruise at 50/55 mph or 70/75 mph and 2500 or so rpm. And much the same with its current 489 engine. Engine temperature is summer/winter related and on a mild summers day at 75 mph engine temperature will start to rise above my preferred 175/180 degrees even using what is probably the optimal rad for a C3 (Dewitts alluminium). On mine now 2500 rpm is noisy. I have tried cruising the M25 at 85/90 mph but it encourages use of the secondaries and fuel consumption drops from mid teens to high single figures and the engine temperature does start to climb. I found the optimum cruise/engine temperature travelling to one of the more recent nationals - it was on one of the hottest days of the year (90+ I seem to recall) and a steady 65 mph kept the temperature down to about 185. Any faster (or slower) and it would run hotter. Oh for an overdrive!
 
Forrest Gump

Forrest Gump

CCCUK regional rep
You’ve got probably 300+bhp ......it’ll go fast with ease.
The feel of the steering and how stable the car feels at speed and on different surfaces may be a factor.
I find the exhaust noise can drone or reverberate in the cabin at lower speeds, so going faster is quieter.

There’s only one way to find.......have fun and take care.
 
kentvette

kentvette

CCCUK Member
Mad4slalom said:
Hi , just wondering what to expect speed wise from a 48 year old vette, what do folk here find their 350 vettes are happy cruising at. Motorway speeds easy? Anyone pushed it beyond ? ( off public roads of course) mine has a frehly rebuilt motor with higher comp, cam etc but really dont know what to expect .
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Our 1978 has a stock motor that has, to my knowledge, never been opened. The auto has been rebuilt and I've worked through a lot of the suspension, bearings etc (just replacing rear trailing arms now).

In our early days of ownership (30 years ago) I would happily run it up to 90mph and beyond (a memorable M1 trip to Billing in convoy with over Kent cars, art a steady 95 springs to mind!!), and I've seen 115mph on the clock, but as the car has got older, speeds have dropped!

The autoroutes here would allow easy 85 mph cruising, but I normally set the cruise control at a max of 70mph, at which speed it is quite happy and comfortable. Beyond that definitely starts to use more fuel and get a tad noisy after a 100 miles or so! The non autoroute limit here is generally 55mph (90kph), and it's really nice at that speed for bowling down a typical French road......

Very rapid acceleration is also a thing of the past - it'll easily outpace a lot of cars without too much effort, and that's fine, but the days of tyre squealing departures are gone!

With your rebuilt engine you'll be fine in modern traffic. You don't mention the trans, or other running gear, but if it's all OK and/or has been refreshed, you're "good to go"!
 
GCorvette

GCorvette

CCCUK Member
This has turned into a really interesting read.

As someone who plans to add a C3 (already would have had it not been for Covid!) I currently have to admire from afar and live vicariously through other's descriptive reporting.

As I would want side pipes and enjoy really long drives, the drone level vs speed factor is interesting to note.

I wonder how many here do make longer trips in theirs, such as to Le Mans or up to Scotland or even beyond? 🤔

Thanks everyone. 👍😎
 
Chuffer

Chuffer

CCCUK regional rep
mickn said:
I tend to stick to 60ish on the motorway, gives people more chance to look and wave and take photos on their phones :ROFLMAO::ROFLMAO:
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That reminds me of an amusing experience 3 years ago whilst barreling up the M6 at a steady 70 on the way to the NEC Classic Car Show . In the rear view mirror I saw piercing ice blue headlights coming up fast and first thought it was the plod ! As it got nearer I realised it was a BMW i8 and thought " here we go , he wants to blast past me and show off " ! So I pulled over to the inside lane to let his ego go by , but no ! He drew along side me , wound down his passenger side window and took a photo of me on his phone , gave me the (y) and went on his way . Neat eh ? :)
 
Roscobbc

Roscobbc

Moderator
When I first had a new system (from the headers back - custom built 3" diameter stainless 'X' configuration with straight thru absorbsion tube mufflers) although not too noisy it has a irritating 'drone' between 1800 and 2200 rpm making cruising below 70mph 'uncomfortable. As the car got more use the 'drone' got less an less (presumably due to the wadding/filling coking-up) and now, several years later the drone has completely gone. Ther downside (if there is one) it that the exhaust has not noticably noisier at higher revs........
 
Roscobbc

Roscobbc

Moderator
Chuffer said:
That reminds me of an amusing experience 3 years ago whilst barreling up the M6 at a steady 70 on the way to the NEC Classic Car Show . In the rear view mirror I saw piercing ice blue headlights coming up fast and first thought it was the plod ! As it got nearer I realised it was a BMW i8 and thought " here we go , he wants to blast past me and show off " ! So I pulled over to the inside lane to let his ego go by , but no ! He drew along side me , wound down his passenger side window and took a photo of me on his phone , gave me the (y) and went on his way . Neat eh ? :)
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A case of 'fossil fuel' envy perhaps?
 
Chuffer

Chuffer

CCCUK regional rep
Nick B said:
60 mph on dual carriageways for me with an occasional rip up to *** just to show people that the old girl can really go!
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I don`t know what I have maxed mine at due to it having the Federal 85 mph speedo but I have given it the occasional squirt and got the needle hard against the stop .
With such wide wheels and tyres and the tendency to tramline the HGV furrows it does get a bit lively though ! It`s much better suited to barreling round Rockingham Raceway :LOL: Unfortunately no chance of getting to do that again :cry:
 
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