65 Chevy II 409 Swap
- Thread starter 409envy
- Start date
I'd somehow missed this whole thread. This is great! I agree about trying to make a jig on the headers (which look very nice) as there are others on here either already building Chevy II's with W power or planning on it. Probably the same deal on the oil pan. I'm looking forward to following this one.
That looks like a hefty Intake valve relief on the piston. Should have plenty of clearance for a stout cam.
How does the hood clearance look like it will be? Is the opening for the SD scoop going to be big enough that hood clearance is a non-issue?
That looks like a hefty Intake valve relief on the piston. Should have plenty of clearance for a stout cam.
How does the hood clearance look like it will be? Is the opening for the SD scoop going to be big enough that hood clearance is a non-issue?
409envy
Well Known Member
I agree about the valve relief. Hopefully it will not drop the compression ratio too much. My builder wants to avoid having to clearance the bore so that I can reuse the block when I eventually upgrade. I don't know what the volume of the valve relief is but I will find out and share the specifics.
We are shooting for 11.5:1 compression. The rest of the combo is pretty standard HP 409 fair. 583 heads, 881 intake port matched and most likely with some kind of carb spacers. Solid flat tappet cam nitrided with edm oil holes in the lifters. We are going to mock up the rotator and heads to find pvc then speck out the camshaft.
As far as the hood is concerned It will clear everything without issue... I have yet to check if the super duty scoop will be large enough to accommodate cutouts for both carbs. I may just make one cut out and then fabricate a plenum with some sheet aluminum and foam to seal it off from the engine bay.
We are shooting for 11.5:1 compression. The rest of the combo is pretty standard HP 409 fair. 583 heads, 881 intake port matched and most likely with some kind of carb spacers. Solid flat tappet cam nitrided with edm oil holes in the lifters. We are going to mock up the rotator and heads to find pvc then speck out the camshaft.
As far as the hood is concerned It will clear everything without issue... I have yet to check if the super duty scoop will be large enough to accommodate cutouts for both carbs. I may just make one cut out and then fabricate a plenum with some sheet aluminum and foam to seal it off from the engine bay.
409envy
Well Known Member
Couple of updates.
Finally finished my header fab. Still have to finish weld all the seams and make cutouts for connection to my exhaust but I am relieved to have the bulk of the fabrication behind me.
Also got a picture from my engine builder. He mocked up the pistons to measure piston to deck clearance and chamber volume.
Specs are as follows
70cc chamber
-.003" piston to deck height.
Compression ratio is ~10.9:1 (less than I wanted due to gigantic valve relief)
Quench distance is going to be .043-.045 with a .040-.042 compressed felpro head gasket.
Finally finished my header fab. Still have to finish weld all the seams and make cutouts for connection to my exhaust but I am relieved to have the bulk of the fabrication behind me.
Also got a picture from my engine builder. He mocked up the pistons to measure piston to deck clearance and chamber volume. Specs are as follows
70cc chamber
-.003" piston to deck height.
Compression ratio is ~10.9:1 (less than I wanted due to gigantic valve relief)
Quench distance is going to be .043-.045 with a .040-.042 compressed felpro head gasket.
409envy
Well Known Member
Coming along in splendid fashion. Weather up here is really helping....... Ready to go by Spring??
Engine should be ready by spring. The rest of the car will take a bit longer but I am anticipating being on the road by mid summer. We shall see....
409envy
Well Known Member
It's being built at Don's speed shop in Berlin CT. Majority of machine work was done by E&G Machine in Wallingford CT.
409envy
Well Known Member
Rotating assembly is back from balancing. I will just say that I should have done more research on my pistons. They weigh 745g each! Piston/pin combined weight is 895g!!! Yikes. I guess I won't be winging the hell out of this thing. The crank also needed a lot of Mallory metal to balance out. We had to take a significant amount of material off of the crank throws to get it to fit the 409 block. It's over and done with now but in hindsight I would have gone with an aftermarket crank and done some lightening to the pistons. Here are a couple of pics of the crank.
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409envy
Well Known Member
3.76" stroke. 427 bbc crank.
FYI
My pistons in my 61 race engine weighed very close to yours all though I had 12.1 Compression and I would wind her up to 7700rpm and only the block can't take that rpm
so I would think you will be fine
I was told that the 3.76 BBC crank supports higher RPMs than the 4 inch 454 crank. That's what we're going with in the 1961 Biscayne drag car. Bore is at .100 so overall CI will be 460 cubes. Going with iron heads (690s).
That Chevy II "grocery getter" will be a fun one to see at Bowling Green
.
Merry Christmas!
TomK
That Chevy II "grocery getter" will be a fun one to see at Bowling Green
.Merry Christmas!
TomK
409envy
Well Known Member
Thanks for all the words of encouragement... I was just shocked that modern forged pistons with a raised pin height would be so heavy. But hey it is what it is. I'm not building an all out race engine (yet) so it should be alright. I will keep you all updated! Merry Christmas!!