Hot Rod Forum banner

1 - 2 of 2 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
I am new to rebuilding engines, but I have an Olds 403 out of a 1978 Buick Lesabre Landau (two door) that I am having to rebuild, so I plan on going all out and go hot rod with it. What I really need to know is what parts are interchangable between Olds and Chevy motors..i.e can I use a 350 (or what ever) cam in it,
Also have a 87 Olds 307 out of a Cutlass that I want to speed up a bit, also needing rebuild..but a quick one..
 

·
Member - AMC/Rambler "guru"
Joined
·
1,781 Posts
Well, you have an easy question -- NONE!! The 403 is an Olds engine through and through, no interchange with Chevy parts. You should be able to find Olds parts easy enough, especially things like cams. If you're putting it back in that boat don't go to big with a cam. You'll need something with lots of low end torque to get decent take-off, especially if you keep the stock rear gears. Go with an RV type cam (more low and mid range power instead of high rpm hp numbers) and a decent aluminum intake with 650-750 cfm carb. The smaller carb will give you better low end torque and snappier throttle response because the air velocity is higher (faster) than a carb with larger holes. Since you won't be turning the 403 to fast it will work fine and only limit top end somewhat, but not enough to be a real driving limiting factor (you don't plan on cruising much over 110 mph or so, right?? :nono: )

Rebuilding a running engine is easy enough. Take it apart then take the block, crank, heads, and pistons/rods to a local machine shop. They will check the block for taper to see how much it needs to be bored, and the crank and rods to see what size bearings you need. The heads will get a simple valve job, but have them magnafluxed (checked for cracks) first. Blocks are usually okay unless you suspect it may have frozen or been run really hot -- then get it checked for cracks also. Talk to the machinist about the parts you want and what you want to get from the car -- cruiser with a bit more power, drag race, etc. He will have some rcommendations. Check for Olds clubs and dedicated sites on the net too, they will certainly have some good info for you.

Once you get everything back from the machine shop it's just a matter of assembly. Use some good assembly lube and double check everything as you put it together. You may want to get some Plastigauge to check the machinists work as you assemble. Everyone makes mistakes occasionally! I didn't do this on one engine I built and discovered the rods were put on the pistons backwards later. I didn't realize it when assembling (okay, I was in a hurry!). This resulted in the rod caps being backwards on the rods -- something I should have noticed since the cylinder position number is stamped on the same side on the rod and cap!! So the crank was a little tight, but didn't seem to tight when built. Burned a hole in a piston due to a plugged carb jet six months later (luckily only one piston damaged -- was an inline six with two carbs) and had to pull the pan to replace that piston. Noticed exceptional wear on that rod bearing, so pulled another and found it the same. Then pulled a main -- it was fine. That's when I closely examined the rod and piston I pulled and discovered the mistake! If I'd used Plastigauge I probably would have discovered the problem, but then again maybe not -- it tirned a bit tight (by hand) but not to tight -- might have been on the low side of acceptable clearance -- who knows?? Out of 5-6 engine builds it's the only one I've ever had a problem with, and I usually trust my machinist and don't check w/Plastigauge.
 
1 - 2 of 2 Posts
Top