kenny

I am new to the forum an I looking to build a performance 400 H.P. Olds 403 at home. Any suggestions?

Olds64

Find a good set of small block heads. I'm not sure what the casting numbers would be but I know 403 heads are a pretty poor choice for a performance motor. I think they have low compression.

kenny

I love the Ferris Bueller quote. I understand the 72 350 heads are best part # 409147. I am looking for a set. Is anyone sure of the comp ratio with these heads and has anyone tested the results?

Olds64

You might ask one of our members 2blu442 if he has any good SBO heads available. He has an amazing ability to find Oldsmobile parts.

J-(Chicago)

Kenny, do you happen to be in IL?

jims2000lt

Early heads. 72 and older should help out. Probably need to go with an Edelbrock Performer RPM untake to make over 400 hp. I have a set of 1970 #6 heads here if interested. Crane springs new valves and 3 angle valve job. They were ported on by me about 10 years ago so nothing crazy for port work. PM me if you need any parts or info. Good luck.

kenny

I am a newbie, I will re-ask my question oin the proper forum.

kenny

Yes, I am from Illinois

1ATony

Welcome to the site.

dman0712

i would use the kb pistons with a set of early big block heads. will put you in the compression ratio of about 10:1. cam with duration in the 230's and lift in mid 500's. Use really stiff valve springs. edelbrock rpm intake, headers. dont spin it over 5500.

Jamesbo

Welcome aboard

Glad you joined up with us.

doc93

Welcome.

If I remember 403 is a small block motor and big block heads won't work.

70 cutlass s

Yes they will work. They are improvement over the stock 403 heads. Most people run a higher compression piston when they use bbo heads.

You have to remember sbo and bbo are similar design the bb is just taller deck. Most people are confused because Chevy are different and most people assume Olds are the same, but they are not.

You also have to use an Edelbrock intake with heads. On the same note using 350 heads are also an improvement over 403 heads.

Oldsguy

Welcome to CO.

doc93

My bad I read the other thread. And it was a good thing I did not know that when I had my 403.