As I’ve posted in another thread, I’ve recently pulled my 68’ camaro out of storage (6 years) and currently in the process of getting it ready to be back on the street. Admittedly, I do not have the skill set to do much of this work myself, so it’s currently in a shop getting the brakes bled, several hoses and lines replaced, new battery, spark plugs, etc. the Borg Warner T10 transmission was nearly shot before it went into storage and leaking like crazy, so instead of rebuilding it’s getting replaced with a TKX that will be here in a couple weeks, along with new gears and posi in the rear that will happen before then.

Now, I’m also being told the carb (Holley 750) needs a new kit, which will set me back ~$500 w/ labor. So I got to thinking… I’ve always felt the 396 has ran like a dawg, even when I bought it. I’ve had 3 different shops agree that it doesn’t feel right for a 396 and attempt to tune it with little to show for it. For more background, the guy before me had an aggressive cam, and a steep driveway… shaved a lobe off the cam lugging it in reverse. So he stripped the motor down and put a more mild cam in (e-928-p). I have a feeling the carb was never rejetted (hasn’t been since I’ve owned it), and fueling may be a part of the issue.

my question is, does it make sense to rebuild the carb and wait to see how the new transmission and gears impact things? Or just bite the bullet and do a Holley Sniper conversion to get EFI?

It seems to me getting a decent carb tune is a dying art… and I’m not sure I want to waste more money having people fiddle with it.

 

What you want to find is someone that dyno tunes carbs let him do the rebuild, I would think there are a few around to support the race world where there is still a lot of carbs. The big difference between carb and EFI is with a carb you must pick what RPM range is most important to you and the engine may run subpar in other ranges. That why a EFI car idles so much better than a build engine with a carb. The EFI has infinite adjustments.



What the dyno tune can tell you is what is missing? Are you running out of spark timing, not enough air or is it running out of fuel. I know the EFI system have self-tuners but a dyno tune is still better to squeeze everything out of it. If you can not find an issue on a dyno then all that is left is Cam timing, Cam Lift or compression.



I don’t keep track of Carb rebuild cost but $500 seem on the high side. I only paid $275 for my Holley Avenger in 2007 that worked great right out of the box. When I rebuilt it 2-3 years ago I spend $35 ish for the kit and maybe 2-1/2 hours. You can buy a new Holley 750 for less then $500.

Keep in mind with the EFI it still needs installed, and if you want to do it nice with metal lines it is not going to be cheap.

 

Thanks Gorn, this makes sense. I guess my follow up for the forum is... does anyone know a good carb tuner in the Bay Area (preferably East Bay), who will tune w/ a dyno?

 

Sorry I don't know the west coast. Normally I tell people to just go to a car show and ask around. Its the best way to find that hidden gems.

How far away is Westech?

https://westechperformance.com/

 

Why don't you save yourself some money and rebuild the carb yourself?
Holley's are not hard to rebuild. Take the model number and match it up with a gasket kit.
I'd put the stock jets/ power valves back in and start fresh. If you have a mild cam, your power valves probably don't need touch.
Then if you want, do like Gorn said and take it to a chassis dyno and have them set up the carb, timing etc.
As for the Holley Avenger kits, I have a friend who hates them. He said it didn't work right from the get go and he sent it back to Holley.
He went with a MSD kit. I heard with the Holley kits, some love them and some hate them.
Remember if you go with EFI, you will also need to change you fuel setup as well.

 

Still EFI will eliminate a lot of maintenance and it will run better and with more power. If the 396 is down on power make sure you know for sure that the motor is good. At least get that oil pan off and make sure there is no metal shards in it.. Also, there are low compression truck type 396 2 barrel jobs from that era. GM even used them in vans and some motor homes where torque was needed but good gas mileage too. Good luck.

 

Still EFI will eliminate a lot of maintenance and it will run better and with more power. If the 396 is down on power make sure you know for sure that the motor is good. At least get that oil pan off and make sure there is no metal shards in it.. Also, there are low compression truck type 396 2 barrel jobs from that era. GM even used them in vans and some motor homes where torque was needed but good gas mileage too. Good luck.

 

I did not mean to say that Carb is better then EFI. When i was a mechanic EFI was my specialty. The first Fuel infection swap I did was in 1987. I also worked are carburetors which included dyno tuning race cars. I am not sure I agree that after market EFI is less maintenance then a carb. I have seen many carb fuel system go 10 years 100,000 miles un touched. Seems like failures of new aftermarket EFI parts is pretty common. I know guys that carry an extra fuel pump and ECM on there cross country trips.

The main befits of EFI is that you have completely adjustable fuel map with no limits other then max fuel. With a carb you can only pick one set of jets so do you want the motor to run good at 5000 RPM or idle? A dyno tuned carb can get you the same HP as an EFI system but only at a certain RPM range. If an engine is running 13:1 fuel mixture at 4500 RPMs the pressure in the cylinder will be the same. For the most parts things like sequential injection and direct injection will help with MPG and the smoothness of the idle. Yes these engines can have more HP but that is because engineers can design a more radical motor and the EFI allows it to be tame at lower RPM not just because of the improved injection.

Examples of what a carb can do
DZ 302 in the first gen camaro. After a race team cleaned up the stock parts and tuned it could dyno a 500 hp (it idles like crap)
My stock 1984 Camaro with a 305 4 barrel with a automatic could get 24-26 MPG on the open road. About the same as my 2000 Z28.

Like most things it comes down to money. You can take your car to a dyno tuner let him rebuild the carb and tune it for around 1K. Or you can spend $1500 on a decent EFI system, another $1000+ to get it installed and another 500-600 getting it tunes. The EFI would most certain run better and have a better torque curve. Is a 5% improvement worth 2K to you, that depends on situation and your focus.

 

The most reliable rig I own is my old '78 square body pickup with a 454 and a Quadrajet carb.
It can sit for months on end with no fuel stabilizer and no battery tender and it always starts up and goes.

 

Alright quick update and thank you all for the great info. Certainly have given me plenty to chew on.

I’m planning on sticking with the carb for now. I just put in the posi unit and 3.73 gears. TKX 5-speed going in next week.

I found a local dyno shop w/ a carb guy. Once the new clutch and rear have some granny miles on them, we’ll see where the motor is at.

My biggest concern is the previous owner shaved a lobe off a cam backing it out of a steep driveway… he said they rebuilt the motor that was only 4 years old at the time, but when I called the shop that did the work some 10 years ago… They didn’t have record of stripping it past the short block. Motor may very well need a full rebuild… so more things to consider before I put a bunch of money into bolt-ons.