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Author Topic:   Olds motor & heads??
Dirt Roller

Total posts: 11
posted April 12, 2004 05:05 PM  
Need help...I run an enduro cutlass with a late 70's olds 350. I ran it hot a couple of weeks ago (240 degrees) and just this past week I found a little oil (maybe a tablespoon) in the radiator. I flushed it out and it continues to run OK. Could I have a cracked head or blown head gasket. It does not run hot and runs OK.

Question 2..It has the olds 3a heads on the motor currently. If they are cracked, what series of heads could I rework and put on the 350 for better performance. A set of 3a's may be the best, but somebody told me to get a 5a or 7a??? What are the valve sizes and what would give me the best performance on dirt track?

Dirt Freak

Total posts: 354
posted April 12, 2004 06:20 PM  
I started my racing by running enduro's. I raced an Oldsmobile with a 350cid. It ran great for the first 80-90 laps and then started to get real hot. It finally quit running and "locked up". The next day it started right up and ran ok. BUT the next time I tried to race it, it never made the finish. Oldsmobiles are tough engines but you probably at least lost a head gasket. Pull the heads and check for blown gasket or head surface straightness. Don't take a chance if you want to finish the next race. Check the water pump, thermostat and have the radiator "flow" tested at a radiator shop.

Dirt Maniac

Total posts: 111
posted April 12, 2004 08:30 PM  
I've included a link to a website that may give you some useful info. If you really want a stump puller Olds, take the nodular crank out of a '68 olds 350 and put it in an olds 403. Then use the #5 heads that came on the 350 and bolt them on. You'd have a lot of torque with all stock components. The 403 had a weak bottom end, so some attention there could pay benefits. Good luck.

Dirt Maniac

Total posts: 174
posted April 12, 2004 11:22 PM  
Be sure and put new bearings in it or it will not last over a night or two.Some have metal head gaskets that can rust though.

Dirt Full Roller

Total posts: 52
posted April 13, 2004 07:23 AM  
they all have a metal shim head gasket from the factory. The heads you want are the 4,5,6,or 7 heads. which will raise your compression about a point and help you flow significantly. Stay away from the 3A,4A,8,5A, and 7A heads. If the heads have a 7 with a small subscript A they are ok just means they have hard exhaust seats.

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