I've been researching my engine lately and have been somewhat disappointed with the numbers ive been finding. Does this motor really only have 185 ponies??
I'm not sure if that number varied beyond that over the years, but I'm pretty sure that's the most that motor ever put out. Stick some high compression heads on there, give it a tune up, and you're good to go! :grin:
I bought a brand new 79 Trans Am with a 403 Olds motor. 185 HP is all it has in the TA form with dual exhaust, 4 barrel, etc... It's a smog motor, a stroked 350 Olds I think. I couldn't figure out a way to make mine run fast back then so I bought a Buick! Paul
You can build it up just like any motor, edlebrock has aluminum heads for it, do a basic rebuild with some hipo parts and it will wake it up alot.
Cool, one more question. Ive been hearing the term "smog heads" a lot around the net, what are they??
SMOGGER...cars with egr's and other pollution control stuff..including lower compressions... I have a stock 1979 ta with the 403....it moves..but nothing great...but I have seen them do plain jain rebuilds with a slight beeefier cam and stock heads from 1970 (and then some) olds 350 .and tear out nice-nice...it builds much better compression.....but ya have 2 watch engine temp....the walls on theses 403 holes are close and ya cant take em down much...they say .30 and never no more.... also seen many with pontiac 400 motors and of course 455's.....and even dropping olds 350 in there....I myself have a 1969 olds 350 motor and been having daydreams about it.....but I like all stock....might be my age :spank: o No:
The 403 is an underrated engine. 180 or so hp,but 320 ft.pds. at a low rpm(2400).That is why there a lot of big GM cars with this engine and 2.41 rear gears.Even the '79 Trans Am's came with 2.41 gears with the 403. The 403 has the same stroke as a 350 Olds,but the cyl. bore is HUGE! Bigger than a 455. You can bolt on some #7 Olds 350 heads ( '71-'72)and end up with almost 10:1 compression. The head bolt holes have to be enlarged ,though. A performance cam and freeflow exhaust would give the 403 MUCH more power. I have a '72 Cutlass convertible that I put a '78 Riviera 403/400 trans in that runs mid 14's using 2.73 gears! The engine is STOCK except for Edlebrock Performer,double roller timing chain and dual exhaust.The camshaft and carb,distributor are stock '78 Riv.
Use any early Olds small block heads on your 403 (the head bolt holes have to be drilled out to 1/2" - earlier Olds motors had 7/16" bolts) a Performer RPM intake, 1 3/4" headers, a mild cam and 3.42 rear end gears...you'll be amazed at the 403's ability. If it weren't for the windowed main web block it would be far and away superior to any other Olds V-8. The thin block casting doesn't take well to a lot of power or high RPM. There are girdles available now to strengthen up the block, but they're expensive. Wanna know more about the 403? Check out www.realoldspower.com PS: Heads to look for are #4,5,6,or 7. But, if you don't want to change cylinder heads, KB/Silvolite has new 403 hypereutectic pistons to raise compression. The stock 403 CR is only around 7.8:1. Glenn
The #7 heads('71-'72) have hardened exhaust seats and the small chambers.Plus,from experience, I have noticed that 71-72 Delta 88's with a 350 4bbl or 2bb engine ,have large valves. just like the 4A 403 heads. A 403 is only good for one .030 punchout. Anything more will result in overheating problems ,due to the siamesed cylinder bores. Certain '77 blocks had solid mains instead of the windowed mains.Still hold up to 6500 rpm. A steel crank from a 330 will fit in the 403 with no mods,but you have to use the 330 flywheel and balancer. Another thing that helps these engines,is using an Olds diesel engine oil cooler . The diesel cars plumbed the oil into the radiator.I took the diesel engine oil cooler adapter and left the lines from a junk car. Found a set of lines and external oil cooler from a Caprice cop car and made it work on my Cutlass.
Thanks a lot guys!! Hopefully when i get a bit more cash i'll do some of these engine mods to my Electra. Would this higher compression ratio make my car fail an emmisions test though?? (not that we have to be tested YET)
also if i put on these 350 heads, can i stay with the 350 valves or should i get the 403 valves installed in them somehow??
Any change you make to the motor is going to effect the emissions. Something to think about before you go tearing off into the motor.
the 403 already have one larger valve in them--can't remember which. The bore size, as mentioned before, is a massive advantage. Don't let anyone fool you into thinking the block is too thin, etc for performance use...especially street type performance use. Stick with cast iron heads and go over to ROP.com and look at some of the engine combos listed for the 403's. Get the larger valves installed (probably get the 2.072 big block intakes and the big block exhaust) to take advantage of the big bore. These motors can make some big hp numbers but for reasonable $$ you can have a great performing street motor. Once you understand the difference that bore size can make on a motor you can start to appreciate this block. Patton
I, personally, would never call the Olds 403 a "pussycat." Sounds like a real car to me. I'm not sure how much difference it really makes in everyday driving, anyway, between a 250 or 300 HP and a 185 HP car, unless you're trying to shave a half-second off your quarter-mile time or trying to pull a tree stump out of the ground with a chain tied to the back of the car (just joking). 185 HP is nothing to sneeze at. If you're not racing the car, what's the point of modifying it to increase the HP? You may never notice the difference in everyday city or hwy driving (assuming you go close to the speed limit and don't intend on burning rubber at every light change). : )
Ya your probably right, its definately not hurting the way it is. Despite the low hp, my electra can still lay down a strip of rubber if i want it to :laugh: But i'll still do a few minor mods in the future when my wallets allows me to. Nothing serious, but i want to start with a true dual exhaust, that'll let er' purrrr nicely!!
