Hi all. This is my first post (after the introduction), and I suspect I will ask many more questions.
I have recently bought a 72 Camaro 350 SS. The engine has received a stroker kit through the previous owner which included dished pistons, camshaft and as the ex-owner described, a cylinder head with very large valves.
I could not get any tech information either from him or form the mechanic who installed the kit but I was able to get the following information:
1. The compression ratio is just under 10.5
2. The valves stay open so long that we now have ineffective power brake. (So I have ordereda collection tank).
3. The rpm was increased up to around 5800

Now my issue is that with such modifications, the car is supposed to have a lot of power, but it does not. To start with it has the wrong carburettor, and once I put in a new one, I will take it up from there.

Before ordering a new one, can you advise me what cfm should I go for? 500 would do the job?

Thanks

 

Personnally I think a 500 is to small, carburator sizing is very subjective depending on who you talk to holley has a carb sizing program on their website I think it will give you choices from 650cfm to 770cfmwith the dual plane manifold you can get away with a little larger carb. Give demon carbs a call and see what they say...... just curious but what is on it now? It would be really adventagous to get as much info as possible on the engine though ...cant they tell you what cam and heads they used???

 

600 or 650 will be fine

 

Thanks guys for the replies. I think I will go with the 650, and even there I am concerned that I might be going too rich?
The chaps here in this part of the world (Lebanon - Middle East) grab what they can lay their hands on, and there are practically no real educated mechanics that do things by the book. It is more like by gut feeling or hear say.
At least this one did the car in an organized manner, and did not mix things that do not go with others, eg wrong cam with the wrong crank etc.
Anyway, I asked what he put in the car and he mentioned the following:
Dished pistons 30 over, "Speed Pro"
Crankshaft for 6500 rpm "Crane"
Camshaft, cannot remember what he said the make was, but it is certainly a very wide ranged one which made me loose the vaccum for the brakes.
The current carb is a Rochester, roughly 450 cfm.
He says the car will need a bigger carb and a good manifold to go with it to get peak performance.

I hope this info helps, keeping in mind that he also mentioned on a previous visit that they installed bigger valves too.

Thanks again, buddies.

 

What kind of manifold is on it. Stock, aftermarket (holly, edlebrock etc)
Does it have headers?
What type ignition does it have?
Did he tell you anything more specific on the cubic inchs?
What type tranny?
Do you know the rear gear ratio?
Lastly why do you think it has the wrong carb?

G

 

Hello rat454
I am not too familiar with the car, and the more questions I am asked, as you are doing, the more I will find out about it.
Ok, I looked at some pics that I have taken and see that it has a "Holley" manifold. Headers, I just remembered that they were manufactured locally. Here is a partial pic from my archive.
I say the carb is wrong because it is too small, either 400 or 450 cfm.
On the ignition, again from the photos I see nothing there, except the distributor, which means no special electronic ignition. See photo below.
Tranny is auto 3 gears but no idea of the rear ratio. I will try to figure it out in the near future.

By the way, the specs on your 71 are awsome, frightfully so

Cheers
F.

[IMG]local://upfiles/6612/0AED4EF8608B4FBCA858A7CDBD30E0DB.jpg[/IMG]

[IMG]local://upfiles/6612/7820262AE6B04520B02DC8BE46A3E568.jpg[/IMG]

 

if you really want to wake it up use an air gap dual plane manifold and a holley street avenger 670 carb it works well on alot of small blocks and they are easily tuned that is what i run and i love it

 

Same here with the Edelbrock air gap manifold and holley,and your ignition looks like a stock HEI distributer.

 

Thanks guys for your input. I had alreadyplaced an order for a Holey 650cfm 4 barrel-electric choke, but was contemplating staying with the Holey manifold. I assumed it to be a good one seeing the previous owner had added it on. Can you look at the photo in the post above and confirm if you recognize it or not. If you do, is it a good one or definately needs changing to theair gapthat you recommended?
Then what about the ignition, what exactly would I need to add to make it more effective?
Thanks for your feed back.

 

Its a decent intake,its almost the same as an Edelbrock performer. Before you switch intakes try out your 650 carb. If you like how it drives with that then no need to switch.