I asked this in the Bench, and was told I would have better luck here. So, I am going to build a 455 Olds for a Cutlass. I have a set of C small valve heads. Do I need to fork out the cash for big valves? It will not be turned over 5500 RPM, and will have a mid sized cam with headers. basically a strong street engine. Should I leave the small valves in them and port them? I am new to these Olds engines and don't know what to expect. Guess they will run, but not for sure. Thanks
I posted this over in the bench too hey John try this sight :Brow: http://www.realoldspower.com/phpBB2/index.php and go to engine builds\ combo's 442.com has a good tech section as well :Brow: http://442.com/ go to FAQ http://442.com/oldsfaq/oldsfaq.htm what are you putting together o No: uzzled:
Just have the larger valves installed in your heads and then blend the valve pockets to meet the larger size. Yeah, easier said than done but blending the bowl up to the new seats is not that hard to do or your machine shop can do it. By the time you pay cost+shipping for a set of heads you have paid for any conversion costs on your heads. There are plenty of other things you can do----go to the "Engine Build/Combo" section over on ROP. The "usual suspects" parts are always helpful....Edelbrock Performer, headers, ignition, etc. Pay particular attention to clearances (and look for some advice in particular on wrist pin clearance if you are going to use TRW forged pistons in this build--many on ROP suggest getting the pin-to-rod clearance checked and recommend a looser fit compared to what TRW recommends). You'll get info both ways on whether or not to use main bearing feed passage restrictors.....you will be ok either way for a mild street motor so don't sweat it (they are cheap to buy). Patton
As with any make of engine, bigger valves give a performance boost no matter how mild an engine you are building (as long as they don't get so big they are shrouded by the cylinder wall). It's up to you whether the performance boost is worth the cash. Any Olds 455 had gobs of usable torque; you may be perfectly happy with the smaller valves.
C'mon Brian!!!! The only thing better than "gobs of torque" is gobs and gobs of torque!!! Patton :laugh:
I knew someone here had specifics on an Olds. The guys on that Olds board seem helpful. I know big valves would help some, but only turning this motor around low 5k's, I didn't know if it was worth the cost. I have converted my Buicks over to Stage 1's, but really think for my use, a ported small valve 70 head would have done almost the same. At least in the seat of my pants. Thanks guys.
It only cost me $100.00 to install the larger valves in a set of olds heads I have :Brow: I'd go for it :3gears: :TU:
Like Mark said---see what your cost would be --you might be suprised. Do it while you have it apart---it's not like it's overkill or anything because remember, lots of the big cars back then already had larger valves and it's not like people were racing those all over the place. Patton
:Brow: and too add .......you may want to install new valves anyway...... uzzled: so you might as well go with the big ones :Brow:
John, another source of information for your 455 Old's build would be Darrel Detweiler. His certified P/S 455 cuts 12.60's on the bias ply with full exhaust. I think Tom Miller is also familiar with the build because he knows the Amish tuner that was directly involved.
And if Tom or Darrel can't find, Brian - - The Amish Tuner, you can easily pick him out of a crowd. He's the one with the straw hat. :grin:
An AMC now? Obviously Marks isn't brand loyal. btw-Got a pic of your W31? I don't think I have ever seen it. As far as the original question goes; The Olds motors like the bigger intakes but the standard size exhaust valves seem to be fine.
Even "big" Olds valves weren't all that big (2.07/1.71). I'm surprised the Olds 455 performs as well as it does. Dropping one into an 87 or older Chevy pickup used to be the hot ticket for a torque monster that would also deliver good mileage and lots of horsepower. They were almost free at the junkyard, and they never wore out. It was alot cheaper than finding and putting a 454 in. Here's another site to look at for info: http://tech.classicoldsmobile.com/ubb/ultimatebb.php?ubb=forum&f=2
