carb numbers and cross reference

[dhoptay]

can anyone help here or give me a web site to check? here is the question, i have a rochester carb merc # 1351-8480a2, sierra # 18-7610. i've changed my manifold and would like to know if i can use a merc #3310-807312a1 sierra #18-7611. not worried about the bolt pattern difference or the fuel input location. just want to know if they are the same cfm. i belive i need a carb that is between 250 and 300cfm. i'm running a merc 120 that had rochester 2 barrel. thanks to all that responed.

 

[bjcsc]

Re: carb numbers and cross reference

18-7611 is spec'd for the 5.7L. I can't imagine it's less than 600cfm. Just looked, I can't find anything that gives the cfm...

 

[Reel Poor]

Re: carb numbers and cross reference

The 1351-84802A2 Is off a 2.5 or a 3.0 liter MCM engines, serial # 6229718 thru C856558.

The 3310-807312A1 is a Mercarb 2 barrell off a 1996-1997 5.7 liter V-8 MCM

I dont think that is going to work on your 120.

 

[dhoptay]

Re: carb numbers and cross reference

thats what i'm thinking to much fuel. think i could take jet out of smaller carb and put in larger?

 

[Reel Poor]

Re: carb numbers and cross reference

No.....CFM volume is going to be your problem with that carb. Plus one is a Rochester and the other is a Mercarb, there different. Get the right carb for your engine or your going to create more problems.

 

[John_S]

Re: carb numbers and cross reference

I believe the MerCarb was built from Rochester designs, after they stopped making them. A main difference that is easilly observable is a single mixture adj screw on the MerCarb vs 2 on Rochester.

The #3310-807312a1 is the 2brl that is on my '97 5.7L. Not sure where I got the info, but believe it is about a 400-425cfm carb. I can tell you it has significant differences from even the 2brl used on the 5.0L of the same time period. Throat size and power valve, come to mind, but would need to recheck the Merc manual. Given its a Merc part, tuning parts outside of stock parts may be difficult to get. Even if a full range of tuning parts are available, you are talking considerable time and effort to tune it for such a smaller engine. Doubt if you gain any significant hp with the larger carb, either.

Repair or replace with the right carb for your engine

 

[dhoptay]

Re: carb numbers and cross reference

thanks guys for responding.guess i'll return it and hope they send the right one this time.