Figured I am far enough along in this project to start the thread on building the new 409 for our 61 Impala, its main thread can be found over in the off topic area as the wheels on it when we bought the car back we OT. Here is a direct link to it: https://www.jalopyjournal.com/forum/threads/2nd-time-around-1961-impala.1320589/ That thread has a complete backstory and history of the car and its ties to the family. The big change this winter though is pulling out the 348 that is leaking out of every gasket and has a head with either a bad seal or guide, and swapping it with a dual quad 409. First thing was needing a block. Well to get that, my grandfather and I had to load up in the truck here in Aloha, Oregon and in 3 days drive to Sheridan, Wyoming and back home. This was back in early May last year. The motor is a late 64 340hp. Pretty complete, only big missing items was the intake and the distributor. Luckily we have a couple spare W motor distributors.
Got home and got a better look at the engine, this was just inspecting and going over all the casting numbers and really seeing what we have. Also in the pile of stuff we got was a 427 big block crank that had the mains turned down to do a stoker motor if we wanted to go that route. We decided not to, so gonna have that crank up for sale soon.
Now with the big pieces home. Kind of put everything away as summer was hitting and got the other cars ready for the season. Did fall into a stash of high horsepower 409 stuff, the bigger 2.5" exhaust manifolds, another oil pan, set of old Jahns 20 over pistons, 11 inch alum bellhousing and the big thing a pair of 690 heads. These are the big hp units. Neat thing with them as well as they are super early 62 units so they have 61 casting dates and we early enough they were not pinned on the rocker studs like most 690s are.
During the summer at Goodguys in Puyallup met a fellow HAMBer and his Uncle with his sweet custom 56 Chevy that has a 409 in it. While chatting asked if he had any spare parts he wanted to maybe sell, but just flat out offered to let us have all the W stuff he had. So a few weeks later met him halfway, had breakfast, talked cars and racing for a bit and the loaded the car up with quite a big of W motor stuff. Super huge thanks for that. Its gonna help out quite a big with the build of this 409. Here is some of the stuff he p***ed along.
Forgot while in the process of this whole thing, also picked up a darn near NOS dual quad intake that is also a super early 62 unit as it again has a 1961 casting date. Kind of fun finding these early pieces that have 61 codes for the 61 Impala. Kind of helps with the theme for this engine is to make it look like Chevy actually did install a dual quad 409 in a 61 car. Also picked up a couple of 327 300hp AFB carbs pretty cheap to be able to convert them over to dual quad units for the manifold.
Now fast forward to October and now it was time to load up the block and take it to the machine shop. One cylinder had a nasty scratch so ended up having to bore the block 30 over. Of the 2 std 409 cranks both were turned 10 already, one just needed a polish job, so went with that one. Got the new pistons swapped on the original rods after resizing and then had the whole thing balanced and then brought all the pieces home.
While picking up the block, dropped the 690 heads off, along with new valves and guide plates to have them gone through. While the heads were at the machine shop, my grandfather and I got to work getting the rotating ***embly into the block.
Hunted & hunted for a 409 I could afford but had to settle for a 348 for a deuce highboy I built about 15 years ago. Looks like you have a good start.
Got the heads back the machine shop next. Also took the cam core and lifters over to Oregon Cam Grinders to have it reground and the lifters resurface as they were all in good shape, no wiped lobe or lifter. Cam is roughly gonna be a L79 grind with a tighter LSA to give it a little more thump.
yeah I hear you on that. We only have this 409 and the parts because we have scored some super deals along the way to make it possible. I had full intention this winter to just be pulling and fixing the 348 in the car currently.
Currently still waiting on the camshaft so painted the tins and balancer yesterday, not gonna bolt the heads down until we can get the cam and timing chain in so can put the cover and pan on. Then roll it over and get the top end together.
Wow, quite a stash of "W" stuff, that intake is the real star of the show, and those chrome rocker covers, man gonna be a spectacular engine bay. You might PM @saltflats about the stroker crank, just a thought.
Chrome covers are gonna be going on the 348 that will most likely end up in the 55 Chevy. For a correct 62 motor, I am stripping the 348 covers and painting them the proper silver the chrome didnt come out till 63. Still need to sell/trade my factory tri power air cleaner for a dual quad unit.
I run one of those in the race car now and have one fin another engine. Also have one that has the rod journals offset grounded to 2.1 still needs the mains and counter weights turned down.
yeah this one just needs the front snout turned down if you want to run a stock timing cover or you get one of those special covers from show car and then run a big block balancer. Contemplated running it, but didnt want the spend more money on the motor as the 61 is just a cruiser where you occasionally put your foot in it. It is a true GM forged 427 crank.
Helped build a 348 into a 409 with a 427 crank and used one of those covers. Found the alinement pin holes were off a bit so had to do a work around so did have a front seal problem.
Yeah I would think with this crank to just turn the snout down at this point. Honestly if I was gonna do a stroker motor, I would have just dropped the cash on a full kit from **** or Eagle so everything is matched and just have to machine the block to it.
Dude, you are killing it once again! I have never owned one, but will always be one of my favorite engines. I can't wait to see it and hear it. My compliment to the chef.
Very cool. Someday I'd like to build the 348 I have and drop it in my 57 wagon. Build it up like a super secret late 57 test mule....
The two heads are different eras, one '62-'63 and one '63-'65. Are they the same chambers and ports and match each other?
He does great work, has done the last handful of small blocks we have built. Only thing he doesn't do is turning cranks because he just doesn't have the machine or space to do it. He has to send those out, just had to change places as the shop in Portland closed recently.
the 409 blocks are all the same outside of it being a p***enger car or truck block. Heads will swap with no issues due to the heads being flat as a board, the combustion chamber is all in the block. You just need the matching intake manifold as the bolt pattern does change between the large heads and the small heads. Similar to the oval/rectangle port issue with a big block Chevy. You can bolt the big heads even on a 348 if you bore it out big enough to clear the intake valve. The only oddball head is the early 58 348's. The early 58 348s have different cooling p***ages and take a different spark plug and the block has matching water ports so they have to stay together. They revised that late 58 to how it would be the rest of the W motors life. The original 340hp 817 heads are basically slightly updated 1147 hi performance 348 heads. Same valve sizes as a 335/350hp 348 and uses the smaller bolt pattern. We are gonna end rebuilding those heads to swap onto the 348 coming out of the car to build more a 350hp 348.
Can't wait to hear how everything works out. Glad to hear that you have one reliable shop doing both block and heads. Enjoy the "ride"!
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