Olds 403 Refresh

[bvanroekel]

After a couple decades in storage, I am finally in a position to start a restoration on my 78 TA.  With all the postings from years past gone, I was hoping to get some feedback on a 403 rebuild.  I am going for something just over stock as this is going to be a fun weekend car and not a race car (just looking for a reasonable, cost effective bump over the 185hp).  There were some articles in the past where people upgraded to flat top pistons to bump up the compression, swapped out the cam, put a 3711 intake on and did a bit of polishing work on the 4A heads (rather than swapping them out for other heads).  This allowed them to get a bit more horsepower, keep things close to stock, not affect the shaker and seemed to satisfy their intentions.  Does anyone have any feedback they can provide on a “lighter” rebuild that slightly improves the stock 403 where maybe the 4A heads can remain?  I appreciate any feedback/recommendations.

[Wallington]

I haven't seen any real news in the last few years but one alternative to the early 350 head swap was the use of KB pistons. Depending on bore required they suit +.024 or +.039 due to The Ford 460 rings (I think) that they use. They were designed to retain the original heads. The gains of the alloy intake is mainly weight savings. I have the stock height Edelbrock even though I don't have a shaker. That was one of the first things I bought 20 years ago after being told the other would not fit. That was incorrect, they assumed every car is a TA. Polishing work on stock heads and restrictive low intake with limited flow is mainly for making things look pretty, and costs that won't make a difference. Likewise, welding up the centre port.
I have the KB pistons, filled exhaust crossover in heads, ported intake and heads, larger valves and roller rockers. The rest is fairly stock. Small girdle, custom cam, Thornton exhaust manifolds and 2.5" dual system. With a borrowed 750 Holley it made 381hp and 481lb tq. Not amazing but double the stock amount roughly, and basically how an early 70s 403 could have been if it existed.