is a 455 too much power in a light car, i.e., early year firebirds. with so much torque, how do you keep the tread on your tires? were 455s standard in some firebirds, 67-69? thanks for the info.
no,the 455 did not come in the birds till 1970.my persomel opinion is you dont need that much engine unless you are planning on racing it.i have put a 350 in my 69 and i can smoke the tires off the rims with it.it is all in what you want.there is such a thing as over kill.with the price of gas now,,i wish i put a 6 cyl in mine now.
I think a 400 is enough power for the Firebirds,like 69firebirdman said if you plan on racing the 455 is better,but for the street NO.The parts car I bought had a 455 in it,that is until the guy that owned it couldn`t control the power and rolled it.These Birds are meant to stay on the ground NOT fly! Darron,Fine 69.
There's an old adage that: "There's no replacement for displacement." In the case of a racing motor, that's 100% true. In the case of a street engine, usually not. Although I have the pleasure of having an OHC 6 in one of my cars, it's on its way out to make room for my 428. Why a 428 instead of a 455? I have a 455 in my GTO. It's a lot of engine - too much engine, in fact. For a street driven car, I should have left the factory 400 in there and spent the money on a good paint job. (I won't go into the engine details.)
Even with the cost of gas in mind, the on-demand power of a V-8 more than makes up for the increased gas use. Though a Sprint OHC motor offers excellent power for its weight, the V-8 still pulls a little harder off the line. (I'll keep the OHC around because it is a really cool looking motor.)
The 428 is a stroked 400. Stroke = More torque at lower RPM. Torque at low RPM is what makes a good street engine, not horsepower. The 455 is also long on torque since it's basically a stroked, .030 over 428. But, unless all that torque gets hooked to the pavement, it's a little bit of overkill (or a lot of overkill).
So, whatever motor is already in the car is always a good starting point - especially a 350 or 400. It keeps the cost down for a new engine. The only drawback of a 350 is the avaialbility of "affordable" pistons. The drawback to a 455 is constantly paying for new tires and more gas.
Just to clarify: The 455 came out in 1970. It became available in the Firebird/Trans am in 71. It depends on what you plan to do with your car. Show, cruise, daily or occasional driver, drag or street race. I plan to go to shows and cruises with mine once restored. I plan to put a lot of miles on it, but keep it in very good condition for a long time. With this in mind: I am keeping it as original as possible, but some minor updates. Also keeping the Sprint 6/4spd combo for good HANDLING and overall performance. Good gas mileage also........ Basically decide what you will do with it, and enjoy it!!!!
As far as gas milage goes I'll bet a well built 400 will get at least the same mpg as that well built OHC6. Depends alot on how often you tickle the secondaries.
Not to start a great debate, but a 400 F/B will have a very hard time getting the same, let alone, better gas mileage than a OHC 6 equipt bird. I got a solid 20 mpg with my worn out 4spd Sprint with 3.55 gears..... :rolleyes:
Birdsprinter: You won't get a debate going because anyone faimilair with 350's versus the 400's know the difference between increased flow at a given rpm.
RPM and flow are only a gauge of how much air the motor is pumping. BSFC determines the amount of fuel an engine will require to pump that air.
The number of factors that go into BSFC (Brake Specific Fuel Consumption) are all of the internal factors of the motor PLUS the external load placed on it. One of those factors is friction. Anyone knows that a six cylinder engine has only about 3/4 the internal friction of a V-8. And, with a lighter load on the engine since it's hauling around less weight, less friction in all the bearings from flywheel to axles, plus the reduced road friction ... well, HP for HP, the OHC is going to do it for less fuel.
Getting back to the question, one thing to add, is the fact that even though the rating system changed, most 455's in stock form were detuned so to speak, so they have all the potential in the world (or in your budget) but you can also make them mild pussycats, in otherwords just a nice cruiser motor.
too much what? what much who?? i'm sorry, but i'm struggling w/ an ohc6. very few performance parts bolt right up. if it wasn't so unique i'd drop in a stock 455 in a second. there are always ways to get the tires to hook.
(sorry guys, i'm just bored-idle hands and all that)
"sixstarved" ,You should talk to Brett (1stgenfirebirdman = brett@cisdirect.com ) he`s got someone up there close by him that has a supercharged OHC 6 , I think he `s getting some REAL hp out of it ( +_400), no need for the 455 then... Bjorn
Scott, I know what you mean. Actually, Q has some good ideas on getting a little more from your OHC. and I'm sure you've been all over the OHC board.
I have to admit, my 67 Sprint-6 stock was nothing to scoff at! I beat up on most V8's in the area at the time... and it really pissed them off to find out it was a stock 6!
Some day I'll get another Sprint to play with, but still wont have the money to super charge it like Brad did!
thanks brett, i'm trying to afford to buy an e-cam from Q if he still has it when i can. right now my #6 wristpin stuck after about 10xxx miles on a .030 over rebuild. so i gotta go .040 over, and buy new pistons-again. a little tip- dont show off your engine revs in sub freezing temps w/ straight 30 weight-even if you're drunk (it was parked in the garage i once had). it probably would've happened anyway-eventually. 5w30 for me from now on. i also want o get an overdrive tranny to replace the th350 i sold to pay bills-oh yeah, and a tree decided it didn't like my pass. quarter during the last ice storm. my poor purple paint. i think i'll save up and buy a lottery ticket.
Scott don't feel bad when i got my new engine w/cam,headers,intake,ect. icouldn't wait to put "all" the sheetmetal back on before a test drive. Well to make a long story short-tie wire holding hood down broke at about 65 -70. Hood became new windshield. lol
Scott, that's one of the reasons I ended up not finishing my 67 Sprint. Back in the early 80's it was next to impossible to find a competnent machinist who knew anything about the OHC, and then try to find a "NEW" cam for one back then.
No internet, no First Gen list, 16 yrs old, and no where to turn... I ended up sending to cam to some place in NY, they welded and reground the cam to specs. New bearings etc... I must have not torqued one of the bearing caps to spec, and it spun a bearing, and damaged the cam, the crank etc... so I shelved that project, and started working on the 68/421 coupe I picked up for $250 http://firstgenfirebird.org/show/closeup.mv?CarID=85 (when I was done)
thanks for the support guys. when i bought this car in '88 i was working at sears, and all the mech.s told me to get rid of it before it ate me. i'm glad i didn't listen. except for the wasted paint job and quarter skin, its worth every penny i put in it since i was 18 and ive replaced or redone just about everything on it at least once. i still have the origional roof, decklid, drivers door, and a couple other parts on the car. wish i couldve done ground up, but i started as a $8000/year trailer trash/wanna drive my hot rod punk. it'll be on the road before i get my licence back.
Darron,Fine 69.
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