Engine/Carb Starting Issues

[brooks]

Hi All,
I'm brand new to the site and am still familiarizing myself with it so I hope I am posting this in the correct place and not duplicating anything unnecessarily.

I just recently installed by rebuilt 340 along with the transmission in my car. It was starting and running fairly well initially but did not have the low end power and throttle response expected after the modifications were made. It also had a hard time starting once warm.

In the end given the situation, the advice I got from my go to guys was that it might be best to replace the old edelbrock carb with a new holley carb. I took the advice given and replaced the 600 cfm weber/edelbrock with a 600 cfm holley.

Nothing else was changed in this process and I can no longer even get the vehicle to stay running. It seems to turn over and start but then quickly stalls. It has also backfired through the carb a couple of times while starting it. Everyone I've talked to thus far is stumped and I have very limited experience with engines and carbs so don't want to fool with it too much without first doing proper research.

I would really appreciate any advice or assistance anyone may have as I am very anxious as this is all that is standing between me and the open road after several years of plugging away.

Brooks

 

[70aarcuda]

Where is the timing set?

Can you tell us what the specs on the engine is?,....you know..cam..heads...compression...and all that stuff

Hard to give advice without know what you got...

 

[brooks]

Thanks for the offer to help. All I have right now is part numbers. I will look up some info on them and then post here. I thought I had them at hand as I did this at one point already but I gave them to the shop that helped me select the carb and forgot to keep a copy for myself. grrr

 

[krazykuda]

What year and kind of car are we working with here?

Electronic ignition or points?

 

[brooks]

it is a 1968 barracuda. not sure about the ignition. Sorry I'm just really starting to learn about this stuff. I will check on it and get back to you.

 

[brooks]

70 aarcuda - here's what I know about the engine at the moment. Let me know if you need anything else.

- SRP pistons (140268) 4.070 bore x 3.313 stroke
- hydraulic roller cam 274/282 and 224/230 duration; .538/.534 lift; 9:1 compression (I think)
- Edelbrock rpm air gap (7576)

 

[brooks]

oh and x heads

 

[brooks]

i think it is electronic ignition and the dyno sheets show the ignition timing was set at 36 - to my knowledge it has not been adjusted since

thanks guys for trying to help. i appreciate it

 

[krazykuda]

Your timing sounds like it's close, I'd start looking into the carburetor.


I would start with checking the float levels.

 

[crackedback]

36 for total might be OK, but if that distributor has 28* of mechanical, it's not going to want to start easily.

IMO, it needs at least 16-18* initial. Try that but don't drive it and see if it starts easier.

 

[brooks]

Thanks crackedback and krazykuda