I am new to olds forum. Just bought a 78 firebird with 455 olds and turbo 400. I think I got a pretty good deal. It is set up as a drag car, fuel cell, stripped down, roll cage and rear has 4.88 gears. Does any one have any ideas or opinions on this combo. I have only experience with chevy engines, I know nothing about olds. Appreciate any advice or opinions.

 

Get rid of the 4:88 gears. Olds 455 will not rev like a Chevy. I would stay at 4:10 or 3:73. Hopefully you have a 7 or 8 Qt oil pan on the 455. Unless you know if the oiling system has been modifided and it at least has ARP rod bolts, I would keep RPM's under 5700/5800 range. These engines have LARGE main bearing and need a lot of oil the the crank plus heavy pistons so keep the RPM's DOWN as I said. Because of the long stroke, the piston speed at 5700 RPM's is probably the same as 7000 RPM' in a Chevy. Till you know more and what has been done to that engine be careful, Ken

 

Yeah 4.88 is way too high on any olds motor.

The 455 has a red line of about 5300 to 5500 somewhere which might sound low, but it's got a hell of a lot of torque

 

thanks for info. has no deep pan, read elswhere about restricting lifter galley, is this something easily done or am i better off pulling the motor and dis and checking everything or looking elswhere. i have not problem with olds, just dont want to leave it scattered all over the track.

 

i might be able to find out what was done to the engine from previous owner. all i know has lumpy cam and j stamped heads.

 

After you find out the info on the engine, pull it anyway and make sure. The "J" heads need alot of work to be just OK. My opion is get the E-brock heads. Out of the box better off and 50 lbs lighter. Next would be pretty much any of the iron heads. Letters A, B, C, G, Ga. Most think "C" the best bet. But with port work and big valves any one will work.
If you are going to use the stock pan, use only the standard pump and make your mods to the oil sys. If you go with the 7 or 8 qt. pan be sure to use the HV pump with the big pick-up.
Be sure to use a name brand timming chain set, and dial the cam in. Check with one of the "OLDSMOBILE" venders that deal with the OLDS engine.
Like what was stated the 4.88's have to go. 3.73's for a street car. 3.90 or 4.10 for racing. 27", 28"tall tire = 3.90's 29", 30"tall tire 4.10's
Also, depending what your plans for the car is, a better stall speed convertor would be a good investment.

Gene

 

thanks for the info. if i do the oil system mods, change rear gears, and tear down the engine to inspect, balance, is it tough enough to take a pounding within reason? from some of the discussions i have read, it is awful easy to spin a rod bearing, and olds parts are not very plentiful here. As for using e-brock heads thats fine are they 1600.00 better than stock early heads or modified heads? I did find out it has msd 6al and 3500 stall converter. i appreciate the response from the other members. thanks Leo