my 403 rebuild

70

Asked by Feb 08, 2016 at 11:46 PM about the 1978 Oldsmobile Cutlass

Question type: Maintenance & Repair

So I decided to rebuild my 403. I bought a kit new
cam and timing chain with valve springs. I also
baought a 1406 edelbrock carb. Long tube headers   
with a turbo 350 trany not posi yet but soon to be. I  
ran it today for the second time. It seems ok just
not much power. So what did I do wrong it wont
burn out either.... Spent so much. Just woundering
what can I check to see why I dont have much
power. Any tips?

23 Answers

5,565

double check the cam/crank positions~

Best Answer
70

How do I check that? I don't have a sencer for that on my 403

1 of 1 people found this helpful.
5,565

there are two dots...make them point at one another~

1 of 1 people found this helpful.
97,165

Is that all you did? Nothing done to the Pistons or the bottom end? If the compression is low it won't make the horsepower your expecting,

97,165

Hey Bob you need to rotate that pic a 180 degrees.

5,565

oops...straight off the press...the dots will point even if eatin' a plate of spam~ was actually amazed that I could find an olds 403 engine picture so easily~ she's real fine my 403...she's real fine my 403 my four oh three~

1 of 1 people found this helpful.
5,565

that carb might be a little fussy...the cam if oversized will lead to TERRIBLE idling~ so there is that...so glad that you selected a standard cam...heavy duty clutches will KILL your foot...a no no, I've found~ Standard oil pumps are preferred...heavy duty will produce so much output they will need to be regulated...will cause leaks and be quite a nuisance...go with standard duty everything...anything else will mean trouble~! ...in my humble opinion~

5,565

this one even has a groovy imaginary line goin thru it~

1 of 1 people found this helpful.
70

Yea I remember I had that lined up rite. Ill do. Compresion check tomaro to see were im at. If I were to do somthing to the bottom end what would you recommend?

1 of 1 people found this helpful.
97,165

All kinds of goodies, but I'm sure you don't have very deep pockets, so first I would have the block checked if you can stay with stock piston size then great if go what the machinist says, 20, 30 over, then go with at least flat top Pistons, and a good set of rings, then have the crank checked, turned and balanced then new crank and rod bearings, oil pump, etc. with the rest of the stuff you already have it should want to tear your head off on acceleration, you may eventually want to go to a turbo 400 trans, a 350 may not last too long under that kind of torque, what kind of gear ratio were you thinking about when changing the rear end out?

70

Ok ill look into that. Well I just bought a rear end off a 396 chevy camaro so ill have to ask the guy. I started to fix my car at age 17 im 20 now and still learing more about all of this so im new to messing around with horse power.

5,565

NITROUS! http://www.andysautosport.com/nitrous_kits/oldsmobile.html

70,275

Precisely dialing in the cam is a key step to getting the most out of your engine. This video is for a SBC but the principal applies to your engine --- http://www.ask.com/youtube? q=how+to+dial+in+a+cam+in+a+small+block+chevy&v=XKtsHqHDX 2A&qsrc=472

1 of 1 people found this helpful.
70,275

I would buy an Edlebrock intake manifold to match the carb.

1 of 1 people found this helpful.
5,565

go juice!~

70,275

If the final gear ratio is really high (which I am sure it is), acceleration off the line will be weak.

70,275

Something like 3.73 would be good.

70

So I checked my compresion all cylinders checked out at 120. Im woundering if it could be my trany or the rear end. Its fast but nust wont burn out

97,165

Like was stated before, it could be geared really high, back then they were trying to get the MPG's up so it would look impressive on the dealers sticker. Hopefully there will still be a tag on the housing that will help.

70

How can I change the gear ratio?

97,165

You have to change the ring and pinion inside the rear differential. Did you find out what the Cutlass has and what is the ratio on the Camaro rear diff you brought?

5,565

https://www.google.com/? gws_rd=ssl#q=1978+Oldsmobile+Cutlass+differential+gears

1 of 1 people found this helpful.
70

I havnt got it yet but I will inform you guys asap when it arives

1 of 1 people found this helpful.

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