i am restoring a 77 electra with a 403 with 31k orginal miles on it. I dont want to put alot of miney in it because it will never be a fast car, i just want it to breathe better so to speak, just wondering what others would do?
Well, there could be some members here with experience with that engine... you do realize it isn't a Buick engine? It's an Olds 403.
I am aware it is not a buick engine but it still came factory in a number of buicks, so i figured someone would chime in. I hear this engine benifits greatly from headers. I know it was common iin firebirds, trans ams, etc so i kow it has some potential
The main problem with late 70's engines is they have open chambered heads, and/so the CR is really low. Duals and hi-flow cats are probably a better investment than headers. If your conscience allows, pull the cats and the EGR and find an earlier intake and carb to put on it.... Power time it.
Are you talking about taking the motor apart or do you just want to check out bolt-on type devices?? I had a '77 Electra at one time with the same motor...loved it. Without changing the cam you are limited in your performance mods..the cam makes the decisions for the motor. No cam swap..then you are sticking with very basic improvements...none of which will make a huge difference. >Exhaust...good dual exhaust set up and as Frank mentioned, you make the call on the cat. >Intake..Edelbrock Performer intake...it's aluminum and will flow a little better than the stock one. You may be moving a little more through the exhaust so you can stand to aid the flow going in. They also make a higher flowing Performer RPM intake but you'd probably need a cam change to gain any advantage from it. >WELL TUNED ROCHESTER. Without this, the first two are rendered a little useless. Get Doug Roe's book on Rochester Carbs and work with yours or possibly opt for a pre-emissions/computerized Rochester. I don't think these cars had any sort of computer "brain" deal in them, but not 100% sure. >Timing...as Frank said....optimizing the timing curve would be a good idea. >Air---No--NOT THE AIR CONDITIONER!!----AIR to the carb. Free flowing air filter and get some fresh outside air to the carb. The car may already have a intake hose cominig off the air cleaner snorkel BUT if you can do some selective surgery on the radiator support you may be able to get the fresh air hose out where it is taking in air from the grille area and not just the hotter engine compartment. Be aware that this is an emissions era car and changing some things might not be as simple as on a pre-emissions car. Not from a regulation standpoint....what I mean is the overall engine system...like the EGR, etc. Make sure if you eliminate something that you first determine what, if any, other part of the ignition, etc may have depended on a signal from the thing you are eliminating. You don't want to start throwing stuff out of whack and chasing oddball problems. My trans went out and I had the T350 rebuilt with a Kenne Bell kit...darn car would get a second gear scratch sometimes. If the engine's coming out then it's wide open on improvements you can make...takes a lot more time to figure out and a lot more $$.
Very good tips from pglade! The 403 actually responds well to simple mods. Back in 1987, I had a 79 Trans Am with a 403 (as most Trans Am's had in 1979). It was stone stock and original, with the cat converter in place, closed hood scoop, a/c, 80,000 miles, and never had so much as a K&N filter installed. With a 2.73 rear gear, and only 185 hp moving a 4000 lb Bird, it wasn't exactly a stoplight threat to Buick GN's. Trans Am's equipped as mine was ran mid 16's. Simple changes: Advance curve kit really wakes up the late model low compression 403 motor. Also, as stated above, create a fresh air intake, and install a 14x3 K&N filter. More advanced changes: Install true dual exhaust, 2-1/2 pipes, and if they make them, headers. Just basic 1-5/8" tube headers will suffice. Olds headers are fairly easy to install because the intake is on the ends (on the 1,2,7,8 cylinders), so the headers look like V6 headers compared to other makes. On my 79 Trans Am, the biggest change came with a rear end swap to 3.42 gears, drum-to-drum, from a donar 74 Trans Am. The car was completely different with a mid 3-series gear. Not sure what your Electra has, or if there are any alternatives for you, but the 403 is a big cube engine with small block heart, so they rev quickly and like gears. Get an Edelbrock Performer intake, which eliminates the horrendous EGR valve. Stay away from the Performer RPM, not sure if you'll have hood clearance issues with that on an Electra. If you really want to really get your hands dirty : The biggest change I made was to install a blueprint W-31 cam and matching valvesprings. I did all this without ever removing the heads (used an air compressor to fill the chamber, and a lever type cheap-o spring compressor), and I actually removed/installed the cam without even removing the radiator. With that cam, the car sounded lumpy as heck, and surprisingly, the cam worked pretty darn well, even with that low 8:1 compression. So without ever removing the heads or touching the shortblock, the car went from low 16's to 15.6's with the dual exhaust, air cleaner, advance kit, and Performer intake. The stock Q-jet remained. With headers and 3.42 gears, the car went 14.6's. Finally, with the W-31 cam installed, and still with untouched cylinder heads, I managed a 13.95 at 101 mph, with most runs in the 14.0 range. My next move was to get some early Olds 350 heads, but my Pontiac 400 was finally done, so the 403 came out. :Brow: The 403 is inherently weak from a structural standpoint, but it CAN take some punishment. I just wouldn't recommend building one for 450+ hp. As a sidenote, I did eventually run a 125 hp nitrous setup (never had it to the track though), and that 403 endured the punishment, despite warnings from Joe Mondello that it would explode.
There are parts made for beefing up a 403 now if you want to make the higher power levels. Go check out some of the builds over on RealOldsPower.com. Plenty of 403's on there running some very serious times. The 403, like the Buick 455, has the advantage of having a large bore relative to its stroke compared to a lot of other motors I think. For example, the 403 has a 4.351" bore and 3.385" stroke. The Olds 455 has a 4.126" bore and 4.25" stroke. The 403 actually used a 2" intake valve which was found on a lot of 455's...but now we're starting to get deep into the motor. Also...be careful which Olds performance parts vendors you select if you get to the point of talking to Olds-specific performance parts vendors. Do some research. One in particular has a pretty bad reputation these days and there are plenty of other knowledgeable Olds parts vendors out there. That is my opinion and I've been messing with Oldsmobiles since before I bought my first 442 back in 1976. Frankly, all the stuff we've mentioned so far is pretty generic stuff..available at Summit, Jeg's, etc. Keep it simple and if you intend to rebuild the whole motor avoid the slippery slope of throwing a bunch of crazy parts at it.
The 403, like the Buick 455, has the advantage of having a large bore relative to its stroke compared to a lot of other motors I think. actually, the bore on the 403 is bigger than on a Buick 455 / 425. i would say "even larger bore than the Caddy 500" but the Buick 455 / 425 already exceed that. by far the most oversquare auto production engine of the era. the only thing that holds a 403 back from being a killer track motor is that the block is really weak. i'm sure the Olds guys have some work arounds and fixes for it but i don't know what they'd be. i'd be looking for recommendations for 1960's closed chamber heads. the 403 is based on the standard short deck "Small Block" Olds design and i would expect most of the early SBO 350 intakes and heads to work.
Bob-- Beefing the bottom end- J&S Proformance (Performance?) sells a halo girdle. Remember, a number of these motors have been built for the Engine Masters Challenge. Maybe that's not the best example as, after all, all the motor has to do is survive through the contest but you get the idea. Heads--you can use the early cast iron 350 heads...#5's from a '69 or #6's from a '70. Can use others like 7's from a 71, etc but I think 5s or 6s will give the highest compression boost. Throw in some porting and the heads should keep up. I'm sure others would just say go with Edelbrock alum heads but now we are talking more $$. I think Dick Miller used the alum heads from the now-infamous Bulldog Racing. There's another guy that is casting the Bulldogs(heads for Olds, not the Buick blocks!) again but I wouldn't be sending anyone any money unless I saw the heads in person and knew they were READY FOR DELIVERY. The guy handling this is a one man operation I think and from what I read, between the lines so to speak, the project is taking longer than anticipated and the same "concerns" seem to be rearing their ugly head again. Too early to tell but, as mentioned, believe 'em when you see 'em. A good friend of mine sent this guy an Olds motor and it is taking A LOT LONGER than the guy said it would...he got the idea his motor was put on the back burner and he had already paid the guy everything he asked for. He basically had to threaten the guy with legal action and I don't know yet if that has done the trick. They need to banish that particular name (Bulldog) as nothing good ever seems to come from it. This is not the "vendor with a bad reputation" I mentioned earlier. Different outfit. This guy, from what I know, is well intentioned but has taken on a little more than he can handle I think....just trying to do too much for too many people. Also..doesn't the 403 use a larger head bolt...may have to open up the head bolt holes in the earlier heads to use the larger 403 head bolts. Install big valves to take full advantage of the BIG bore. New oil pumps should be taken apart and checked over for clearances...maybe machine the body for optimum gear-to-cover clearance. The 403 rods were supposed to be beefier than the 350 rods also.
Ditto on all of the above. I would also add, if you're inside, change the crank to a forged one from a 64-67 330 (requires a matching flywheel, damper and a good rebalance, or at least a nodular 350 crank from a 68-73 350. It's a drop-in. Good set of pistons, deck it at .020 in the hole, and put on the J & S girdle. I believe 440 Mopars have a bore this big as we used something from there when I built mine years back. We did use the 7A heads, but put in the 2.07 intake and 1.62 exhaust valves and used a JM20-22 cam. Did have to open up the head bolt holes (have this done at a machine shop, don't try it yourself, can get into some significant side loading on the head bolts). You also have to move one of the dowel pin locations to mate up the 350 heads to the 403 block. Again, have a machine shop do this or you'll get the intake on crooked, if you get it on at all. This combination in an 86 442 with the stock ignition, full power accessories, and the stock 200R4 and 3.73 GM 8.5 10 bolt (that came in the 1984 Hursts and the 85 and newer 442 models.... same as a Grand National rear), ran in the low 13's and passed Illinois emssions. Ditching the stock computer controlled distributor and some good carb tuning got this car into the mid 12's consistently and tows a trailer with his golf cart behind it to the track. An Olds 455 also bolts up directly into a car made with a 403 (your Buick, big Olds 98, automatic Firebirds, etc). It's the easiest and cheapest path to more performance, but a little tight on the A/C unit and Power brake booster. We always felt that if Olds had stayed in the performance game in the 70's (instead of pulling their best performance engineers and making them emissions engineers) and put this engine in the 79, 83 or 84 Hursts (or any G body Cutlass), they wouldn't have got the image as the Gutlass Cutlass and it wouldn't only be us old farts that grew up with a different image of Oldsmobile. But Mother General was dictating what engine went in all the cars back then and it was just a matter of time........R.I.P.
Amen! The "Gutlass Cutlass" nameplate still cracks me up. The name actually came from the ill-fated 1950's Navy jet fighter the Chance Vought Cutlass, which was woefully underpowered, and pilots quickly dubbed it the "Gutlass Cutlass". Poor Oldsmobile, I guess they didn't see that one coming...:blast: But back to the original question, I believe he was just looking for basic hop ups, which would (again) be an advance curve kit, fresh air intake and good filter, maybe a change to the Performer intake to eliminate the EGR, and true dual exhausts. One odd thing about the 403 engine's exhausts on the Firebirds, the drivers side pipe went across to the passenger side manifold, THEN combined into a single pipe to the converter, unlike most single exhaust systems that simply had a Y-pipe into a single pipe. There's quite a bit of horsepower to be found by simply going to dual exhaust, even more with headers.
Bob--Beefing the bottom end- J&S Proformance (Performance?) sells a halo girdle. yeah, but Corbet is asking for "cheap". ain't no way in hell a decent block girdle or the machining to install it can be considered inexpensive. Remember, a number of these motors have been built for the Engine Masters Challenge. Maybe that's not the best example as, after all, all the motor has to do is survive through the contest but you get the idea. what was it, last year better than a 1/3 of the contestants didn't even complete their 3 first round pulls? yeah, Engine Masters might be okay for a "proof of concept" test run but most of the guys going there scare the bejeezus out of me if they would consider putting their motor in a street or drag car. the AM&P Buick motors are a pleasant exception to that rule.
Does anyone know if a 455 crank fit into the 403? That would make about 500 cubes. Even if you keep it at 403 cubes, I agree that the heads and cam should be top priority. :TU:
guys, thanks for all the replies. I think i have a better idea of my options. However i am looking at bolt on type of parts, exhaust, headers, carb, intakes, etc. like i mentioned before this is a four door 77 electra. It will never be fast, i just want it to act more like a big block v8
Does anyone know if a 455 crank fit into the 403? That would make about 500 cubes. i'm assuming you're asking about the BBO crank. there's no way a Buick or Pontiac crank will work. all 3 have different bore spacings. i kind of doubt it, what with the 403 being a short deck block. the mains in the block would also be undersized for the crank. Corbet, you need to read this: http://www.442.com/oldsfaq/ofe403.htm
Mill the heads to raise the compression do some pocket porting, get an aluminum intake and a cam and headers if they're available. and check out http://www.mondellotwister.com/
