Time for a motor swap!?!? Advice needed
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Registered User
Joined: Apr 2013
Posts: 515
From: Wilmington, DE
Time for a motor swap!?!? Advice needed
I've been doing my research and hunting for a 350 olds. Irony comes in many forms as the gentlemen putting a roof on my building happens to be an olds guy. He has a 69 cutlass S he purchased in 1997 with a 71' 350 (this is all he said/she said chatter). The color of the motor and valve covers are gold (who knows if that original). Anyway, we got to talking and I'm going to hear the motor run in a few weeks. If it sounds good, doesn't smoke or burn oil the price we agreed on was $350.00. Where I need help: Are there any casting numbers or earmarks I should be looking for to verify the year or the motor? Any tips on what to look for besides the obvious? My trans is a 2004r with 10k miles and a shift kit. The rear is a 3:73 EATON diff with stock convertor. I'm assuming the rest of the drive train can handle a stock 350. Where I'm getting caught up are the details. Will my power steering assembly bolt up? Can I use my carb from the 307 (its the stock roch)? The motor in question has points and I'd like to use my HEI, will I have to change much? My radiator is brand new so I'd like to stay with that set-up. If the motor sounds and runs good my plan is to replace the oil pump, pan/valve cover gaskets and when the time is right drop it in. ANY and ALL opinions, information and advice (as always) would be wonderful. This will be an on-going project and I will be posting pictures of the new motor when I go to see it. Thanks as always.
Registered User
Joined: Dec 2011
Posts: 7,286
I've been doing my research and hunting for a 350 olds.
================
Why is the engine getting replaced, pray tell?
Irony comes in many forms as the gentlemen putting a roof on my building happens to be an olds guy. He has a 69 cutlass S he purchased in 1997 with a 71' 350 (this is all he said/she said chatter). The color of the motor and valve covers are gold (who knows if that original).
=================
All the 330/350's thru 1976 were Gold.
It is by FAR more likely to be a #8 headed 73-76 350 with an EGR valve, in my experience, but maybe the tale is accurate. Ck the numbers.
Anyway, we got to talking and I'm going to hear the motor run in a few weeks. If it sounds good, doesn't smoke or burn oil the price we agreed on was $350.00.
================
Ck the oil for looks and smells. Look at the spark plugs, and do a compression test if you just CANNOT get into a rebuild in the worst case. Have a vacuum gage and oil pressure gage on the motor during the test run, and record [write down] what they say.
Where I need help: Are there any casting numbers or earmarks I should be looking for to verify the year or the motor?
==================
Yes, lots of them.
Search here for VIN stamp location photos, etc.
The FIRST thing is the number/letter on the corner of the head, near #1/#8 spark plug. 1971 should have "7" heads; 1972 has "7" with a TEEEEENY subscript "A". 73-76 has the big "8", and after that you get the smog era lightweights with a HUGE "A" same size as the number:
2A, 3A, 4A, 5A, 6A, 7A. While sereviceable, they may not be what you are after.
Then find the BLOCK ID aft of water pump, fwd of intake, between oil fill tube and oil pressure sender. 395558-2 [larger "2"] is the 68-76 350. Other than that, ck the Olds wiki for what it is.
Oil fill tube will have a long number- 1st digit is model year: 1002003 for 1971 for example.
CARB should have a long number, LH side, aft corner:
7042250
70 = Rochester
__42 = 1972; 43= 1973; 28 = 1968 [yeah it's stupid]; etc.
____250 = basic 350 Olds Engine; '251 typically BB; '252 Tornado; higher #'s possible
INTAKE manifold - first look for an EGR on the LH side. That tells if 1973+ or 1972 & earlier. Also it will have a large ID number in the depression aft of the water crossover. See the INTAKES thread here for photos and what each number means. 1971 intakes are around #10-11-12 I believe. #16 or 17 will be smog era 1973+.
Any tips on what to look for besides the obvious?
=============
the obscure?
:-)
My trans is a 2004r with 10k miles and a shift kit. The rear is a 3.73:1 EATON diff with stock converter. I'm assuming the rest of the drive train can handle a stock 350. Where I'm getting caught up are the details.
Will my power steering assembly bolt up?
Can I use my carb from the 307 (its the stock roch)?
The motor in question has points and I'd like to use my HEI, will I have to change much?
=================
Yes, the engines are externally identical. Really you are just changing the bore size. And a zillion details of construction. The carb should bolt right onto a factory 4-bbl intake. You can use the factory A4 for a cheap aluminum unit that will be easy. I found that the Edelbrock Performer was such a colossal waste of time to get the carb attached right that I gave up on it and went A4- NO WORRIES. You might have to alter the HEI to suit. Depends on how your motor likes the timing curves your computer [I assume] uses. Worst case, go to pre-computer HEI, tailor the HEI to suit the motor, and remove the "CHECK ENGINE" lamp. Or use it for amusement: pop hood, "yep, engine is still there!"
My radiator is brand new so I'd like to stay with that set-up.
===============
Sure. I put a beasty 403 into my '85 442 with the 307's radiator and it stays right on 210, once I got the HEI timing straightened out. Long story elsewhere.
If the motor sounds and runs good my plan is to replace the oil pump, pan/valve cover gaskets and when the time is right drop it in.
===============
TIMING SET
ALL the freeze plugs
Dismantle your distributor, clean, and put fresh grease in the upper bearing supply cavities.
Use your CAR's exhaust manifolds for easiest hookup, otherwise everything may have to change, exhaust-wise. Use the new motor mounts for THE CAR, it does not care what V8 is in there. New hoses. New plug wires. New plugs. Rot like that.
================
Why is the engine getting replaced, pray tell?
Irony comes in many forms as the gentlemen putting a roof on my building happens to be an olds guy. He has a 69 cutlass S he purchased in 1997 with a 71' 350 (this is all he said/she said chatter). The color of the motor and valve covers are gold (who knows if that original).
=================
All the 330/350's thru 1976 were Gold.
It is by FAR more likely to be a #8 headed 73-76 350 with an EGR valve, in my experience, but maybe the tale is accurate. Ck the numbers.
Anyway, we got to talking and I'm going to hear the motor run in a few weeks. If it sounds good, doesn't smoke or burn oil the price we agreed on was $350.00.
================
Ck the oil for looks and smells. Look at the spark plugs, and do a compression test if you just CANNOT get into a rebuild in the worst case. Have a vacuum gage and oil pressure gage on the motor during the test run, and record [write down] what they say.
Where I need help: Are there any casting numbers or earmarks I should be looking for to verify the year or the motor?
==================
Yes, lots of them.
Search here for VIN stamp location photos, etc.
The FIRST thing is the number/letter on the corner of the head, near #1/#8 spark plug. 1971 should have "7" heads; 1972 has "7" with a TEEEEENY subscript "A". 73-76 has the big "8", and after that you get the smog era lightweights with a HUGE "A" same size as the number:
2A, 3A, 4A, 5A, 6A, 7A. While sereviceable, they may not be what you are after.
Then find the BLOCK ID aft of water pump, fwd of intake, between oil fill tube and oil pressure sender. 395558-2 [larger "2"] is the 68-76 350. Other than that, ck the Olds wiki for what it is.
Oil fill tube will have a long number- 1st digit is model year: 1002003 for 1971 for example.
CARB should have a long number, LH side, aft corner:
7042250
70 = Rochester
__42 = 1972; 43= 1973; 28 = 1968 [yeah it's stupid]; etc.
____250 = basic 350 Olds Engine; '251 typically BB; '252 Tornado; higher #'s possible
INTAKE manifold - first look for an EGR on the LH side. That tells if 1973+ or 1972 & earlier. Also it will have a large ID number in the depression aft of the water crossover. See the INTAKES thread here for photos and what each number means. 1971 intakes are around #10-11-12 I believe. #16 or 17 will be smog era 1973+.
Any tips on what to look for besides the obvious?
=============
the obscure?
:-)
My trans is a 2004r with 10k miles and a shift kit. The rear is a 3.73:1 EATON diff with stock converter. I'm assuming the rest of the drive train can handle a stock 350. Where I'm getting caught up are the details.
Will my power steering assembly bolt up?
Can I use my carb from the 307 (its the stock roch)?
The motor in question has points and I'd like to use my HEI, will I have to change much?
=================
Yes, the engines are externally identical. Really you are just changing the bore size. And a zillion details of construction. The carb should bolt right onto a factory 4-bbl intake. You can use the factory A4 for a cheap aluminum unit that will be easy. I found that the Edelbrock Performer was such a colossal waste of time to get the carb attached right that I gave up on it and went A4- NO WORRIES. You might have to alter the HEI to suit. Depends on how your motor likes the timing curves your computer [I assume] uses. Worst case, go to pre-computer HEI, tailor the HEI to suit the motor, and remove the "CHECK ENGINE" lamp. Or use it for amusement: pop hood, "yep, engine is still there!"
My radiator is brand new so I'd like to stay with that set-up.
===============
Sure. I put a beasty 403 into my '85 442 with the 307's radiator and it stays right on 210, once I got the HEI timing straightened out. Long story elsewhere.
If the motor sounds and runs good my plan is to replace the oil pump, pan/valve cover gaskets and when the time is right drop it in.
===============
TIMING SET
ALL the freeze plugs
Dismantle your distributor, clean, and put fresh grease in the upper bearing supply cavities.
Use your CAR's exhaust manifolds for easiest hookup, otherwise everything may have to change, exhaust-wise. Use the new motor mounts for THE CAR, it does not care what V8 is in there. New hoses. New plug wires. New plugs. Rot like that.
Thread Starter
Registered User
Joined: Apr 2013
Posts: 515
From: Wilmington, DE
The motor is being replaced because this fella has a 455 that is going in the 69. My motor is being replaced because I want more power. My stock 307 with headers is good for 15.3 @91, while the car is my daily driver and runs like a champ, I want what the car should've been built with originally..a 350. I appreciate all the number information as I will have to take a good hard look. If it is a 73+ I wont be as excited but lets be frank, the factory 307 is nothing to write home about. My carb was replaced and has about 15k on it so I'm glad to hear I can keep it. Motor mounts were also replaced 3 months ago. I have headers on the 307 currently, and will put new ones on when the 350 is dropped in. From what I've read if this is a stock 71 350 it'll be around 250 horse, 350ftlbs and 8.5:1, that sounds great to me! Thanks for the info
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