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#1
09-28-2013, 04:04 PM
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Round port exhaust manifolds 1966 Bonneville??
I have a set of 1974 SD 455 roundports laying around and am making a game plan for upgrading/rebuilding my 421 in my 1966 Bonneville this winter. I have a good 455 crank, sd rods, sd heads and sd exhaust manifolds, SD 455 block has freeze cracks. Considering boring the 421 to 455 bore, dropping in the 455 crank, rods and heads but I am pretty sure the sd 455 exhaust dumps on manifolds will be in wrong place, aside form headers is there a round port exhaust manifold that will work? I might just broom all the 455 stuff and use the money to have the stock heads cnc'd at sd perf and rebuild stock short block, buy long branch exhaust manifolds, or do that but put 455 crank/rods in, then machine valve reliefs in the pistons to match the original heads, just sorting out my options, thanks for input, Smitty
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1966 421 Bonneville convertible 1974 Transam w/ 600 hp efi 455 I build and modify Transmissions and rear ends. http://www.smittysengtrans.com/ |
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#2
09-28-2013, 04:12 PM
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The SD exhaust manifolds should work as they both have rear dumps & if I remember correctly the exhaust dumps for your car are in the rear also. I don't see any problem in using them in your car.
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#3
09-28-2013, 04:29 PM
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You will need the long branch round port manifolds that fit '65-'70 B-body and '67-'69 F-body cars.
The factory 455SD manifolds only fit '68-'72 A-body and '70-'81 F-body cars. |
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#4
09-28-2013, 04:41 PM
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Ram Air Restorations did have them but their tooling broke. No ETA on that yet that i know of. I do know of at least 3 people that are looking for round port long branch manifolds.
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Brad Hansen 65 Cat Ventura, 66 Cat Vert, 63 GP |
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#5
09-28-2013, 10:25 PM
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! small correction on the round port exhaust manifolds, They work on all A-body cars 68-77 & they also work on the G-body which is Grand Prix & Grand Am. They also work on the X-body which is the Ventura or for you cheby guys that the nova body. Yhis is a fact as I have them on my 73 GTO & had them on my 74 GTO.
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#6
10-01-2013, 05:01 PM
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I highly doubt you will fit any factory style ROUND port manifold in 65-66 B body, there will be great interference with the power steering gearbox, and possibly the frame, motor mounts, etc. Now if you had D-port heads, you could use long branches easily.
Your best bet with round ports in a 65-66 fullsize is to give Mark at Mad Dog Headers a call. I recently put his part # 9169 (modded to 3.5" collectors) in my 65...fit is great. Does require a small starter though.
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Red\black 65 Grand Prix 467 E-head stroker, Viper T-56 6-speed, 4.10 spool |
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#7
10-01-2013, 08:19 PM
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68 1/2 ram ll and 69 ram IV Firebird manifolds will work. You will also need the b body oil filter adapter.
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 Mike McCarty You can drop the line, but you'll never kill the spirit!Pump gas 535 w/Marcella cv/1's. 11.0 compression, 4000 stall, 3.73 gears, 275 radial, to the axle exhaust, 3470# w/driver. 9.49 @ 140..........so far |
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#8
10-01-2013, 09:22 PM
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Quote:
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#9
10-01-2013, 09:59 PM
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Quote:
 The '68 RAII and '69 RAIV F-body round-port manifolds (factory or repro) are the only ones that will work in the '66 B-body with 455 SD heads. |
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#10
10-01-2013, 10:11 PM
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I have a set of new, never used RARE round port long branch manifolds for 65-70 big cars. Let me know if you're interested in buying them.
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[SIGPIC][/SIGPIC |
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