I have been crating my engine parts up for the rebuild I hope I will be able to afford soon and could not remember which style B4B I had packed away when a definite older style became temporarily available so I picked it up. I see what I think are two bolt patterns of which one I know is for an unknown to me Holley model as used with the over the counter Stage II B4B but I love my Quadrajet. Is the second bolt pattern for a Quadrajet (or spacer plate)or is there an adapter plate to run a Quad verses the Holley? Final question if I want to run this beautiful patinaed old B4B what number Holley carb is correct (anyone got one just in case)? I image it won’t line up with factory scoops either way? Sorry for the barrage of questions my memory on these details has all but left me but thank you in advance for any help or suggestions. Kindest Regards, Fritzenshiftin
John the center set of bolt holes are for original style afb carbs but also line up with q jets . But u will need a adapter for a q jets large rear bores to work on that intake. The outside pattern are holley. A holley i would have prefered to use for day 2 use back then would have been a holley 4780 800cfm or a 4781 850cfm for a healthy 455. both are double pumpers Cant answer scoop question! Im a 67 guy and havent spent anytime on 70 up cars
That’s why you are better off with the Q Jet opening. You can run both the Q Jet and a square bore carb (Holley or AFB). Since the intake has both bolt patterns, both carbs bolt right up, but the larger secondaries of the Q Jet will hit the edge of the Holley opening. To bolt a Holley on an intake with a Q Jet opening, all you need is a thin plate to square off the opening and some guys don’t even use that. That is why I bought the Q Jet version of the SP1. I configured my fuel line to be compatible with my Q Jet and 1000 DP. Carburetor changes are a 15 minute affair.
I know Mark Demko got one of the first SP-3 intakes for his 350. It was a Holley opening. I believe he had a machine shop open up the carburetor opening so he could run his Q-jet.
cobwebs in my head...... I believe that the B4B carb pad was relocated forward from the factory position to do a better job of centering the (Holley) carb on the intake runners. It made sense at the time to do so. The newer Performer Series moved the carb pad back to match the stock factory location which locates the carb primaries closer to the heat crossover passage. Better for street use? They do make spreadbore to squarebore adaptors, but they take up vertical space which you might not have a lot of under to hood. Never like the thought of those in any case. Might be best to see if you can trade off for the newer (used) Performer Series as there are no issues in lining up the with the factory scoops, nor the use of your Quadrajet. Tommy
Thanks Tommy, gonna have to weigh the options with alignment,patina,& whether to use my Poston Ram Air front spoiler and eliminate most of those issues
John, I modified that style of intake to fit a Qjet by enlarging the face to match the spreadbore gasket.
