i'm going to transfer all existing valvetrain from my 403 to a set of olds #4 heads (came off of 67' 330) anyway, i intend on keeping the cost as far down as possible. i understand i should use my 403 intake valves becuase they are 2.00's and no one has ever said anything about the exhuast valves. any suggestions on exhaust valves for my heads swap?  

If you intend to use the 330 heads and the valves from the 403 heads,if the valves in the 330 heads are smaller than the 2.00 you specify you will have to open up the seats in the 330 heads to accept the bigger valves.You may be better off re-doing the heads since you would need machine work done anyways to use the bigger valves.If this is not the case,you will still need to have valvework done to mate the valves to different seats.Just lapping them may do it for you but I doubt it.I am not an olds guru but you need to look at other things as well.Stem diameter and valve stem length come to mind to name a few.Good luck,hope this helps.  

Why are you switching heads?? Better chambers,flow.Lack of smog humps/passages??Remenber a smaller chamber will give you a higher comp ratio but chamber size could cause your compression to be too high for pump gas use.Keep this in mind,there are plenty of olds guys here who can give you better info so hang on a while,it will come.The info I gave you is just basic stuff,It applies in a general manner so dont take it as gospel.Good luck.  

If you use the bigger valves...you will have to have the heads machined to accept them.

You raise compression by a full point at least (ie 8.0:1 up to 9.0:1).  You will also have to drill out the 330 heads to accept the bigger head bolts used on the 403's.  Not a big deal.

You will also have to have hardened valve seats installed in order to use unleaded gasoline.

Go to 442.com and check out the FAQ section.  There is a TON of information on Oldsmobiles...as well as opinions and experiences of people who have swapped an early small block head onto a 403.  

See told ya  

i'm trying to raise the compression in the engine, so i can get the power that that engine is capable of producing for me. basically my current heads have 83cc chambers and the heads i'm going to use have 60cc chambers which after having them milled .015 should give me somewhere between 9:50.1 - 10:1 compression, wich is very streetable and that's what i'm after since my t/a is a daily driver and i even lug the kids around in it from time to time.. i'm on a mission to get the most out of it. becuase that engine is fro a smog era and was rated at 185hp with 325flbs torque. wna dwhen i'm done with what i've put together already and what i plan on doing i should be upwards of 320hp and god knows what the torque will be but it'll be fun to find out.. 8 yrs in the making now hopefully i'll be done before the year is up, wish me luck brother.. any further info you run into would be appreciated.. thanks for getting back to me.>>>>> bandit burning out.  

thanks bud, i had read about the hardened valve seats, and drilling the heads bolt holes to accomadate the larger 1/2" holes in the block.. i've actually had time to do a little reaserach for some time as i've been looking a set of similar heads for some time to make this happen and i ran into deal i could'nt refuse price wise. i'm trying to keep cost down as much as possible that was reason for wanting to swap ove all the internals from my 403 heads. thanks again! bandit burning out  

yeah you make a good point, it would cut down on my down time if i heads redone while the car is running and then i can just swap the heads over.. thanks.. bandit burning out.  

have you thought about milling the existing heads down about .030" to bump the compression?... a lot of buick guys do this with the later smog heads then block off the heat riser too. You will of coarse want to change the pushrods to a custom length if you don't want to worry about piston to valve clearance and as long as you stay below .500" inch total lift on the olds the rocker arm geometry should be safe still. If it was me i'd just have them milled... so much cheaper and it gets the job done all you'd be out is some gaskets and materials. make sure you check the intake too.  Sometimes they seal up fine other times they too must be milled a bit to seal up any machine shop should be able to complete this task for about $150 for both heads and the intake.
brandon  

i've never heard of this, but thanks for the info. i'll look into it.  

People often approach the situation of putting bigger valves in smaller heads as a logical way to make more power. Bigger is better right?  However this doesn't always provide the performance that they are looking for.  A lot has to do with the shape of the combustion chamber.  Sometimes when bigger valves are put into small heads the effective flow across the valve head is reduced due to shrouding of the valve by the shape of the combustion chamber. Which means that you may in fact loose power and while making your valve train heavier. No valves are 100% effective in terms of flow area. An example: a small valve that is 75% effective vs. a big valve that is 50% effective... You have to do the math and see if going to bigger valves are actually worth the effort.  I would mill the heads and investigate head gasket options.

-ZK