403 olds T/A advice

If your goal is 350-400 hp, the Edelbrock heads are more trouble than you need at this performance level. Get a pair of the early 350 Olds heads. That will get the compression ratio up, gain better airflow and avoid problems with the shaker and fuel pump. Perform a good valve job, remove the A.I.R. bumps from the inside of the exhaust port. The Edelbrock camshaft is very conservitive IMHO. Look to Comp Cams or Lunati. Im pretty sure the Performer intake will work with the shaker. Look for some good headers and exhaust system, my freinds used a Dynomax system that he bought from Napa. He ordered it for a 73 T/A so he didnt have to mess with the catalitic converter. Install a good timing chain set, if the stock timing chain has flaked much nylon off the teeth, remove the oil pan and clean the oil pump pick-up. All the nylon will be stuck in the screen, blocking oil flow. Install a 2500-2800 converter. Look to American Performance Enginering: Larry @(765)437-0185. Get the distrubutor recurved, have the Q-jet rebuilt by The Carburator shop. If you do these mods I would be shocked if you didnt have at least 400hp. Dont listen to the Chevy guys, you can make a Olds run very well, and it doesnt cost nearly as much as they would have you to believe. You just have to spend the money in the right place! Good luck!


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Tom, that price is EACH!!!

But yes, I think they're good heads. But they're not needed to get the power you want, as Matt69 said before.

There are no bolt-on-and-go Edelbrock heads available for the 402 except the RPM's, anyway. Prob. not the best choice for what he's doing, but the choice is ultimate his.

Finding the 350 heads stateside would be fairly easy, but he's in Belgium. Makes things a little harder. Plus you'd want to up the valve size to 2.000 intakes and 1.625 exhausts.

I have found :
1968-72 OLDSMOBILLE CUTLASS/442 350 CYLINDER HEADS
68-76 OLDSMOBILE 350 CYLINDER HEADS CASTING #7

Can I use these for my 403 Olds 0.20 Bore and with my Olds stock oversized ( 0.20 ) pistons
Are the olds #7 heads gonna give me to much compression ?

And with the rest of my list of parts that I'm going to use to rebuild the 403 :

edel. carb 750
edel. manifold 2711
edel. camshaft 3712
edel. timing chain 7813
hedman headers hed 58078
magnaflow mpe 15899
b&m converter bmm 20412
pioneer flex-plates pio-fra-102
oil pump hp ses-7-60-08-01


Thx for any comment ...

There’s a build up of a T/A w/Olds 403 HERE.

Hey guys , please comment my set-up so far please !!!
Can I use the Hedman hedders 58078 with the Magnaflow kit 15899 on my trans-am ?
Or are the Dynomax hedders 86030 better ? They cost less...
Flowmasters instead of Magnaflow ?

if your into the stock look. just deck the block .30 and mill the heads .30 and you will need to mill the intake to line the holes back up. tons of compression just from that. but that motor doesn't want much compression. the parts are not strong enough to take it. a buddy of mine built his up. took it to a drag strip and on his 4th pass the crank broke into 3 pieces.

I posted this on another thread, but it is relevant here as well, prob. more so. I would consider it a "Must Read"!

Joe Mondello is the King of Olds performance, as far as I'm concerned. If I were building an Olds (again- already did a 455 in a '76 Cutlass) I would not even dream of doing it w/o parts and/or info from him.

So, here ya go.

A list of Joe Mondello’s (aka “Dr. Oldsmobile”) articles, including two on just the 403 are located HERE.

In one of the two articles, there's a "kit" w/about all the parts you need except the cam. You'll see it. Then , it ran about $1700 w/the optional parts, $1500 w/o them

I might mention that the chambers of your heads are 70cc, IIRC. They will also need to have the head bolt holes opened up to match your 403's 1/2" head bolts.

Im not sure about header part numbers, I just know the Hooker headers fit great! My personal preference for mufflers is Flowmaster, Magnaflow is also a good brand. Comes down to personal preference.

Once again, look at realoldspower.com for build advice. Those guys know what they are doing. Call Mondello, Dick Miller or Rocket Racing for additional advice.

Im going to say it again; YOU CAN MAKE A OLDS RUN GOOD! You just have to know how to go about doing it. All the Olds guys I know or have suggested will be more than happy to provide help or advice. Good luck!

Joe Mondello is an Olds guru, but be aware that he is really no longer involved in the day-to-day activities of the company that bears his name. The company is in Paso Robles, CA, and Joe is in Tennessee.

Hey guys ,

I have ordered the KB405 pistons and I'm going to use my stock 4A heads on it !
These heads are going to be rebuild at the shop a little for better flow ...
but I don't know what head gaskets to use ???

I hear good things about cometic mls head gaskets , but BAD things as well about them leeking under high compression !

My Keith Black pistons are gonna give me 9.5 : 1 compression .

What gaskets to use on my 403 Olds ?