Joined: Tue Dec 29 2015, 12:20PM
Location: Finland
Posts: 3
Hello to you all
I'm restoring a 1963 Imperial Crown, original California car with low miles. I was wondering if anyone has slapped 440source stealth heads on one of these 413 blocks? I heard there might be valve to block bore clearance issues? I know max wedge engines had valve notches machined to block but max wedge valves were bigger than stealth valves.
I'm asking this because I want to convert my engine running unleaded fuel and go to EFI at some point. Putting on hardened valve seats to these old heads would be more expensive than aftermarket heads.
Can't say for sure but the bore may be smallish for the 2.14/1.81 valves in the stealth head.I would ask 440 source if anyone has done it.I would think a competent machinist could remedy the problem if need be.
Joined: Wed Nov 17 2010, 03:28PM
Location: florida
Posts: 1311
the heads will fit but what is critical is knowing piston deck height for valve clearance ,pushrods may need to be resized,and to establish final compression ratio as to not reduce and kill performance.not sure if stealth heads have different plug angles than stock ,which need to be considered for header clearance.
Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
VintageSpeed wrote ...
Hello to you all
I'm restoring a 1963 Imperial Crown, original California car with low miles. I was wondering if anyone has slapped 440source stealth heads on one of these 413 blocks? I heard there might be valve to block bore clearance issues? I know max wedge engines had valve notches machined to block but max wedge valves were bigger than stealth valves.
I'm asking this because I want to convert my engine running unleaded fuel and go to EFI at some point. Putting on hardened valve seats to these old heads would be more expensive than aftermarket heads.
Thanks for your help
I have a set of the 440 source stealth heads but have not yet installed them. The plan is to put them on a 440 anyway so not really relevant to your question. My understanding is that the stealth heads mimic the design of the later factory heads very closely hence the "stealth" designation.
You could install the heads onto the block and see if there are any valve clearance issues with the cylinder walls. I do not think that would be very difficult to do with the engine out of the car and flipped upside down.
Your comment about the cost of installing the hardened valve seats is interesting. You should be able to get the 8 hardened exhaust valve seats for about $100 and add about another $100 to the cost of a valve job to get them installed.
I had a 1966 Newport 383 2 bbl several years ago with the 516 heads. I got a valve job done on those heads and installed the hardened seats along with the bigger exhaust valves. That certainly helped the heads breath.
However, I would suggest looking at the aluminum stealth heads unless you really really want to keep the heads that you have.
Also, I started the process of cc ing the stealth heads that I purchased. I will finish that process when I actually plan to use the heads. I think that I posted the information somewhere on the dry dock. Most of the chamber volumes were pretty consistent around 82 cc as I recall but there was one quite a bit smaller. I have no idea how this compares to other aluminum heads but it is worth checking the chamber volumes.