81 C3 engine questions
Thread Starter
Heel & Toe
Joined: Jan 2015
Posts: 20
Likes: 0
so here are some pics of my heads
I thought it to be a little weird they seem to be stock from looking into the numbers but if they replaced the cam on it which it sounds like they did then why wouldn't they change the heads.
one thing when i was looking around online and I saw pictures of these heads the little retaining ring on top of the spring looks different, on mine its red maybe they replaced them?
any suggestions on what type of heads would be a good replacement for these? If I go and change out the heads would the pistons and cam still work good? or would I have to replace those at the same time.
I am going to run a compression test this weekend and see what it is running to help figure things out hopefully.
what you think from looking at them.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
AFTER telling us that you are a mechanic in another field...so you know how to approach 'things'...WHICH IS GOOD.
You have to stop and REMEMBER or CONSIDER....if the 'bottom end' ( crank, rods and pistons) are out of an engine that was in the era of when the HP and toque was killed....so the metal and manufacturing processes used to make them were lessened BECAUSE the engine did not NEED to have super bad @ss parts in it because it was not going to make the power like the earlier years...AND.....IF you go and slap a set of head on it that reduce the combustion size....thus increasing the COMPRESSION ( depending on deck height and other variables). This increase of compression on bottom end parts that 'are not all that'...can 'possibly' cause for an issue IN TIME. Not writing that it will happen immediately...but it seems CRAZY to put performance parts (small cc heads) that can increase 'things' when the bottom end parts are NOT AS GOOD and what was USED when the performance parts were used.
So having 76 cc heads now and throwing on a set of 64 cc heads 9 if that is what you are planning) can 'possibly' cause a problem in time...especially the integrity of the connecting rods.
DUB
You have to stop and REMEMBER or CONSIDER....if the 'bottom end' ( crank, rods and pistons) are out of an engine that was in the era of when the HP and toque was killed....so the metal and manufacturing processes used to make them were lessened BECAUSE the engine did not NEED to have super bad @ss parts in it because it was not going to make the power like the earlier years...AND.....IF you go and slap a set of head on it that reduce the combustion size....thus increasing the COMPRESSION ( depending on deck height and other variables). This increase of compression on bottom end parts that 'are not all that'...can 'possibly' cause for an issue IN TIME. Not writing that it will happen immediately...but it seems CRAZY to put performance parts (small cc heads) that can increase 'things' when the bottom end parts are NOT AS GOOD and what was USED when the performance parts were used.
So having 76 cc heads now and throwing on a set of 64 cc heads 9 if that is what you are planning) can 'possibly' cause a problem in time...especially the integrity of the connecting rods.
DUB
Melting Slicks
Joined: Jul 2009
Posts: 2,091
Likes: 40
You need to find the DATE casting number code. It's raised and on the passenger side rear on small block. It is usually 3 or 4 numbers or letters that tell the Month and year it was cast ......sometimes there is an extra digit...this was the shift during which it was cast . It's raised , but dirt , rust grim etc make it harder to see than the engine cast number you found.
Your going to have to look again .....it's there , raised , not stamped , you might have to clean the letters to make them out for sure. Example might be ... C 74 2 ..... This is March 1974 2nd shift.....there were some variation depending on year with using letters or numbers...but it's a short group of raised letters and or numbers your looking for. These raised letters and parts numbers are on most if not all the cast components .....so you can see when each part was cast .
Ok ....I see the head pics......those look like late 70's heads to me . Is there any specs of blue paint on the heads ? The latter 70's motors were factory blue.
Last edited by LS4 PILOT; Jan 21, 2015 at 09:23 PM.
Race Director
Joined: Jul 2001
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Thread Starter
Heel & Toe
Joined: Jan 2015
Posts: 20
Likes: 0
Does anyone know how to post a video on here I will take a short video of it running to let everyone hear the car, definitely sounds like camshaft has been replaced.
I updated the first post with all the pics in one spot for new readers as well, I will keep posting new pictures there. Thanks again guys! we will figure out whats in this engine soon enough lol
Safety Car
Joined: Nov 2008
Posts: 3,717
Likes: 551
From: Seattle Washington
Congratulation's You have what is known as a "010" High Tin Block the best of the best. OK not so quick on the high 5's. It was the rage to find one of these in the early 80's because a higher Tin content in the block made it stronger and there for more desirable for performance builds. However this has pretty much been proven false, some of them probably had more Tin, but how to tell ? Built from 1969 to 1979 they were used in Vettes Camaros and Lots of Trucks etc. Both two and four bolt Main Caps. Although the "010" block might not be as sought after as it once was, there is nothing wrong with it, and there really isn't any better production block than it either.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
The high nickel/tin content being associated with numbers on the block has been proven to be false many times over.
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Safety Car
Joined: Nov 2008
Posts: 3,717
Likes: 551
From: Seattle Washington
As it sounds as though You are a True Hot Rodder and an Aircraft Mechanic to boot its sounds as though You are out to have Fun with this Car. You couldn't of picked a better choice that a C3 and a Small Block Chevy to work on both of which respond well to Hot Rod.
I would pick up a couple of Books on the SBC, there are many out there. Two classics are " How to rebuild the SBC" and " How to Hot Rod the SBC". I'm not sure how well they have kept up with the changes in the last 20 years or so, but none the less are great reads.
I for see You installing some modern aftermarket Heads, Cam and Intake Carb set up on what You already have, along with a 4 speed overdrive Trans that has a lower 1st gear. Just as many before You have.
Mild to Wild the SBC has been built, and yes an all Aluminum SBC with Dry Sump Oiling and modern Fuel Injection makes a very capable
Aircraft Engine. ( as in 2/3rds scale Mustang )
I would pick up a couple of Books on the SBC, there are many out there. Two classics are " How to rebuild the SBC" and " How to Hot Rod the SBC". I'm not sure how well they have kept up with the changes in the last 20 years or so, but none the less are great reads.
I for see You installing some modern aftermarket Heads, Cam and Intake Carb set up on what You already have, along with a 4 speed overdrive Trans that has a lower 1st gear. Just as many before You have.
Mild to Wild the SBC has been built, and yes an all Aluminum SBC with Dry Sump Oiling and modern Fuel Injection makes a very capable
Aircraft Engine. ( as in 2/3rds scale Mustang )