Besides the exhaust, a good tune up and make sure everything is working properly. You could also change gears out back. It wont add any power but you'll improve the acceleration.
1st time Cutty owner
- Thread starter psycobilly64
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Build the driveline first and don't worry about messing with the 307.
Decent rear gear (3.73's) etc. Depending on your goals the stock 7.5" rear will do okay but if your going to put money into anything, your better off spending it on an 8.5" or Ford 9", etc.
Move on to the transmission and have building properly to handle the power you plan on making. Actually, for reliability have it built to handle more than you plan on making.
Get all that worked out and it will make the 307 more fun to drive but will be set up and ready for a bigger Olds engine. I would personally go with a 425/455 big block. 😉
Decent rear gear (3.73's) etc. Depending on your goals the stock 7.5" rear will do okay but if your going to put money into anything, your better off spending it on an 8.5" or Ford 9", etc.
Move on to the transmission and have building properly to handle the power you plan on making. Actually, for reliability have it built to handle more than you plan on making.
Get all that worked out and it will make the 307 more fun to drive but will be set up and ready for a bigger Olds engine. I would personally go with a 425/455 big block. 😉
It's likely the olds is gonna be a long term project car (one I can drive as I fix it up). I'll probly have to get ahold of the parts I need a little at a time and build some things on the bench to be put in later.
I swapped the non original 5A 307 in my 88 Cutlass for a 403. The Olds 350 or 403 is a DIRECT bolt in. The 425 or 455 is pretty close, causes minor issues for some due to being taller. Even a low compression, cheapo 403 like mine has tons more torque. For the one or two mpg it is worth it. I added 3.42 gears in place of the stock 2.56 gears, gained .6 in the 1/8 mile. Add a 2 1/4" true dual exhaust with good flowing mufflers. Also a major tune up, make sure no check engine lights are on. That and 3.73 gears will help a lot. You will only run at 2000 rpm at 60 with stock tire height with 3.73 gears.
Sounds like I need to start lookin for a 403 then :wink: . I had one in a 77 Rivi and one in a 79 T/A and loved them 🙂
He said he had an 307/OD trans. The 307/ TH2004r was the only option avialable in 88 with either 2.56 or 3.08 gears. That's why even up here, we got the Olds engine option, instead of the usual sbc 305. I would get at least a big trans cooler and make sure the TV cable is set right before you move after a 403 swap.
I would go with a 350 or 403 both good engines. There are a lot more 350 engines out there and if you are on a tight budget I would go with a early 350. I think the last year of the solid main web was 75/76. If you can find a low mile engine that was well looked after you could build on that. Early heads, after market cam,intake,headers you will have a nice street runner.I would build the engine to run on reg gas and get good gas mileage. 342 gear with over drive will make the car fun to drive and save gas as well.373 would give you a little beter 0 to 60 but will cost you a little mpg. Is this a daily driver or a weekend only car.Its a good idea to have a budget and a goal for your car.Take your time and plan your build, you will save time and money and it will turn out better.
This is my daily driver and only vehicle right now. I want to stick with mods on it that can be done in a few hours for now. I will be on the lookout for a 403 I can build on the stand though..... :wink:
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