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#1
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81 T/A what engine would you build? 400 or 455?!?
Hi,
I've got an '81 Turbo T/A WS6 with TH350,3.08 posi rear and the current 400 needs some work, it has 6X8's and a Torquer II with Holley 750 which is a really bad combo for this engine What would you do? * redo my 400 mildly with 6X-4 heads and Summit 2801 cam (no boring, honing etc) * Have my 455 block bored, honed etc. and build it with the 6X-4 heads and Crower 60916 cam (this will be more $$$ to build) I am not gonna race this thing, it will be a cruiser. I like torque and I don't rev my engines wildly. Maybe a little wheelspin now and then. Would there be a big difference in fuel economy between the two (given I drive both the same relaxed manner)? BOTTOM LINE; WHAT WOULD YOU DO?!?!?
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'67 GTO hardtop coupe 400 2bbl (sporting a 4 bbl) '70 GTO convertible 400/400, matching numbers, Currently getting worked on again, body in the bodyshop, engine at the machine shop etc!!) '71 LeMans Sport T41 Coupe restomod (GTO clone with Judge stripes and wing) 400/350 '71 LeMans Woody Wagon 400/350 patina project 1975 Grand Am 400 factory sunroof project car |
#2
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Personally,I'd go with the 400/6x4's with an 068 Pontiac grind & Edeltork Performer/Q-jet.
It's a proven combination. You'll have TONS of good streetable bottom end & the 400 should yield some better fuel economy than the 55,depending on your driving habits,of course) |
#3
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455 that way you won't regret you didn't build it bigger & badder. Losing sucks.
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I'm older now but still runnin, against the wind. Bob Segar. |
#4
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I have the the same combo but with a crower 60919.
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74 Formula Below motor destroyed last fall 469, 6X-4's, 72 Intake, Ramair Manifolds. 3 inch exhaust with x-pipe Custom Roller Cam, 1.52 Roller Rockers Quadrajet done by Cliff 3:42 gears 12.061 @ 110.74 12.092 @ 112.43 12.128 @ 111.71 New motor 461 stroker Edelbrock 87 cc dport heads Performer RPM Same Ram Air manifolds, and quadrajet Results will be posted after the track |
#5
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I have the almost exact same 400 combo in a '73 Grand Am with 3.23 gears and the car is a beast to drive. Lots of fun without being too much effort and hassle in the maintainability\drivability part. Putting a 455 is fun and I'd do mine too, but if it needs to be bored and honed, that is just extra cash that may not be available at the moment (especially if you need a sleeve or two like mine =P ).
I'd put a 301 turbo back in just for fun though ;-) |
#6
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i don't think either one you can go wrong with
but it's always better to use the bigger cubes if you can besides, the heavy second gens and the 455 torque make it a nice setup i am in the same situation i want to redo the 400, but also have the 455 in the garage. i know my 400 tune well, and know what i am after, with the 455 i'll have to rethink a few things, minor though |
#7
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No Replacement for Displacement! Go with the 455 if you can.
.
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#8
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My 400 in my '78 4spd is a beast.
400 with 6X-4s, factory intake, q-jet and summit 2802 cam. 3:42 posi. Anyone that says 70s cars are slow, i make believers with this thing. It's a blast, makes tons of streetable power and runs like a mofo. |
#9
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NICE LOOKIN CAR MAN! If it were me and the 400 is original, then rebuild you can have a rowdy setup still...but if it's not...455!...Leave the 400 sticker on it and it will kinda be a sleeper!
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#10
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I would go with the 400 block with an aftermarket 4.25 stroker crank
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#11
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Can't go wrong with either motor, I put a 455 in my 81 with the Crower 60919 and it runs great, not missing the 301 at all.
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#12
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You can't beat the torque of a 455,I own a W72 and an L75 car,........455 all the way baby.......
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1973 T/A Buccaneer Red L-75 A3,83k mi. #'s match 1979 T/A Atlantis Blue W-72 WS6 23k mi.survivor#'s match 1999 T/A Navy Blue 60k mi....babied 1968 442-gone but not forgotten "Oh,you can think about it,.....but don't do it!" Sheriff Bufford T.Justice |
#13
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Thanks for your replies so far!!!
As it stands right now the choice is almost certain going to be the 455. I'm waiting on Ken from PPR to get me some shipping info on the 5140 I-beams. Got a lead on a nice set of 6X-4 heads. Will use the Crower 60916 cam with matching valvesprings I'll leave the TH350 as is (the way it shifts I suspect it has a shiftkit fitted) with the stock converter. Keep the headers (unknow brand) that are already on the car, just need quality gaskets to prevent leaks. I'll also ditch the Holley 3310 I got right now. Looking into getting a Q-jet done by preferrably Cliff R. A quality Q-jet might win back some mileage (providing I can keep my foot out of it!) However I do think I'll need to save up for subframe connectors...I don't wanna risk any thing with the body and all that 455 terror-torque .
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'67 GTO hardtop coupe 400 2bbl (sporting a 4 bbl) '70 GTO convertible 400/400, matching numbers, Currently getting worked on again, body in the bodyshop, engine at the machine shop etc!!) '71 LeMans Sport T41 Coupe restomod (GTO clone with Judge stripes and wing) 400/350 '71 LeMans Woody Wagon 400/350 patina project 1975 Grand Am 400 factory sunroof project car |
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