Hello, Can any one give me some insight into swapping my current (gutless) 307 for a 403 engine? The 307 is terrible driving up hills with friends or luggage and doesn't offer decent acceleration for passing. I want to continue to run the wagon with the stock engine management system and make it look as stock as possible. The other issue is finding a decent crate motor supplier and a company to do the de install and re install. Currently the car doesn't require a smog test but if I move states to say... California I'm wondering how that will effect me? Thanks for your help and advice. Cheers, Fenn
A swap should not be a problem. The 403 and 307 share the same external dimensions. I have a 403 in my wagon. The stock 403 is hampered by low compression and poor breathing heads even though they have large intake valves. The compression can be remedied with KB Silvolite pistons (the only good off-the-shelf I know of). Number 5, 6, 7, or even 8 heads are a big improvement and will also up the compression. The huge bore on the 403 (biggest of any Olds) un-shrouds the valves and improves the flow. I have No. 5 heads that have big valves, port work, and filled exhaust crossovers on my 403. It has no problem getting my 4200 lb Vista moving with a pretty mild cam. I'm still experimenting with timing to get the most out of it without detonation. The CCC Quadrajet may be a problem. I obviously don't run one since my wagon is a 67. The carb can be re-jetted, but I don't know how the computer is handled. I suggest you post some questions on the forums at Real Olds Power. Don't get a crate motor unless you want to be disappointed. Oldsmobiles are too far from the mainstream. There are some good builders who specialize in Oldsmobiles, just avoid Mondello out in California. Someone who specializes in Olds will be better able to match the correct camshaft with the heads and short block. The 403 is a good engine if you don't over-rev it.
Hello Vista, Thanks for your advice. I had read that Mondello was worth looking at so I'm interested to hear more on why they should be avoided. I guess the engine management system will be the big issue. I want to ensure if wont attract attention and will pass any smog requirements. As you say the 307 and 403 look the same. With some black paint I hope it will look like the engine bay of the 1977 model. I've seen two engine suppliers on e-bay. Perhaps not the best source? There's also a new old crate olds 350 on there at present from 1987 for $1500.00 apparently never been used but after this time I'm sure it will only have problems. The reason I mention the 350 is I wonder if t will be easier to marry up with the CCC management system. In the meantime ill look at those parts you mentioned. Cheers, Fenn
Some may consider it sacrilege, but you can always swap in a 350 TBI motor from a 91-92 Custom Cruiser. If you're not doing the work yourself it could get expensive getting the computer and sensors wired in, getting an electric fuel pump added, and things like that. California will let you use a same year or newer engine that was stock for that car. It depends on the tech who smogs it, though. If you put in an LT1 from a '94 Roadmaster wagon they might be OK with it. They might insist it HAS to come from an Oldsmobile (and why I recommended the 350 TBI above). They DEFINITELY won't let you put a truck motor in it although a 5.3L LS engine would be ideal. You could use a Camaro/Firebird 5.7L LS engine maybe. I'm glad I live in Texas because I could put in whatever I want. I could go so many ways with an '88 Custom Cruiser. Part of me wants to see a 6.2L truck diesel backed by a 700-R4. Part of me wants the LS engine with a 4L60E. Another part of me wants to try out a 4.3L Vortec V6 with a 4L60E. And then there's the fuel miser in me who thinks there's enough oomph in a 2.8L/3.1L/3.4L Camaro V6 engine with a 5-speed stick and the right gearing out back (3.08 or 2.93 or something). I've even entertained thoughts of even smaller engines like a 2.2L Ecotec 4-cylinder or the supercharged Cobalt SS 2.0L version backed by a 6-speed manual. A 350/403 should be fine, but if you think you're moving to Cali, go for a 91-92 car-based TBI 350. It seems the "safe" option to me.
Fenn, I have no direct with Mondello in California (not to be confused with Mondello in Tennessee), but I've seen numerous posts about shoddy workmanship. Check with some of the web sites dedicated to Oldsmobiles for recommendations of vendors in your area. Regarding the crate engine: I assume you are referring to this 350 on Ebay. Based on the casting numbers, that is a 76-77 block with No. 8 heads. That's not a bad engine, but I'm not so sure of the 1987 date if it is new. I would consider changing out the timing gear set since it has a plastic cam gear. BTW, another nice thing about staying with the Olds family is that all the accessories and brackets will bolt right on. No modifications to the wiring harness, engine mounts, or fuel lines will be necessary. The basic architecture of the Oldsmobile engines remained the same from 64 to 87.
If you check the Olds Forum, you'll not only find used and rebuilt motors, there's a large thread about dozens that've been ripped-off, etc. by Mondello Cal.!! Joe sold it quite a while ago, and the current employees/owners don't care about anything!!
Hi All, Thanks for your comments. The engine change has been on the back burner as I was made redundant but now want to push on with the project. Regarding the Olds Forum, I've found two. Classic Oldsmobile.com and Oldmobile Forums Which is the one you suggest? Thank you. Cheers
