spunner

My engine builder is insitant on me getting Barry Grant 750's for my 475HP 7.4's. Problem is they are stupid expensive. I have located a pair of Edelbrock 750 CFM marine carbs and was wondering if anyone has had a problem with them.

Thanks!

rdoactive

I'm guessing here but either:
A) he has more experience tuning holley type carbs for his builds
B) he gets a bigger markup on the BG carbs
C) both
There are arguably advantages and disadvantages to both styles. But if he's going to stand behind his motors with the BG carbs, go with them.

scarab31

What mods did you do to get to the 475hp? Did you start with 330 or 365 initally? I have 365hp 454's and want to get to the 450hp range.

wjb21ndtown

Talk to GetRdone... He's stated before that he thinks that BG understates their CFM ratings on their carbs (meaning a 750 is probably more like a 780 - 820cfm carb). Your engine builder probably knows what he is doing and wants that extra cfm to get you up to power. BG's are expensive for a reason, the work. Edlebrock carbs are alright, and street enthusiasts love them because they're super easy to tune, but most race builders do not use them, and I'm guessing there is a reason behind that (which their are, they are not as tunable as a BG or Holley, from what I understand).

A Holley 4150 is probably a better replacement if you want to save some money, but I would talk to your guy first, let him know your concerns, and see what he says.

spunner

Started with 330's. Bored .030 over, 9.6:1 forged pistons, 781 heads (new valves & all), Indmar exhaust, Comp Cams XM284HR cam, roller rockers, air gap intake, MSD ignition. The 475HP is an estimate based on the specs. Until I obtain carbs I can't get it on the dyno to get hard numbers.

tx911

Dont expect a bG 750 to necessarily outflow a holley 750. The BG's do seem to be more honest with flow ratings compared to the HP series holley carbs which are generally 950 or 1000cfm carbs. Like stated above the edelrock/carter carbs are easy to tune, and gererally go some time between rebuilds due to the fact that there are no gaskets below the fuel line. I also think they tend to run better out of the box. That being said, it is not the carb I would choose for your build if it was me. I am not a engine builder or a carb guy for that matter, but it seems to me that any serious power has a holley style carb on it for a reason. The BG's look nice, but I dont know much about them except some poeple have issues with them out of the box, but if the guy doing the dyno session is comfortable with them then that should be fine. I personally would look into a professional carb builder like prosystems to get me where I need to be. I just ordered a carb from them and it did not cost anymore then a off the shelf carb. You will also get a carb you can build on if you decide to go bigger with the power later on. You might also find that you combo needs more then 750cfm.

getrdunn

iTrader: (7)

I would think the choice of BG 750's would be ideal for what you have going. Like jwb said your guy more than like knows what's best and has put 2 and 2 together. Carbration is extremely important to complete your already expensive project. I know it sucks to stick more money into it at this point however doing anything less than what your advised is like putting perfume on a pig. LOL... I am facing the same thing right now and have been all over the board on carbs. i have read way more than I care to even talk about and am probably more confused than ever also. It's best to take his advice as mentioned because if you have tuning issues etc. he can always throw this at you. "I told you so" Just know also you can get the marine version with fuel line for just over 600.00 if you look around. I am going to take the advice of another on the board and call Pro Systems. NOT cheap either but I don't want to be tuning all summer. The season here is short.
Good luck,
John

scarab31

Thanks. Post your dyno report when all said and done.

spunner

emailed the guys at ProSystems. They really do know their stuff. Gave them all my specs - displacement, lift, duration, compression, all that stuff. Based on that they are saying I want something 820 CFM to 840 CFM. 750 is too small. Not to argue with my builder, but carbs are all these guys do... However, much like BG they are proud of their stuff. I am sure they are worth it, but having a hell of a time opening the wallet... Will have to decide something soon...

getrdunn

iTrader: (7)

Isn't this fun