Breakdown of my 402 rebuild [Archive] - Chevelle Tech

: Breakdown of my 402 rebuild


FlameOut
Jan 2nd, 08, 4:19 PM
I think I finally have everything I need to start gathering parts for my 402 rebuild.

Stopped at the machine shop today. He showed me my heads (049) and what will be needed. Almost all of the valves were pitted, and should be replaced. He said it was most likely caused by storing the motor with water in it, or bad head gasket. There was also quite a bit of play in about 6 of the valve guides and a few chips around a couple of the seats, so thse will need repaired/replaced

Now the block. He suggested it be bored .030 over (so would that be 4.155?) so therefore would also need new pistons. He mentioned an 1/8" dome? He said I could probably get by with honing and .005 over rings, but I would be getting blowby, and the .005 rings were more expensive

I'm probably going to get all of the parts, and have them build it ($500). I was concerned about cam breakin, but he said he would come pick my car up, and flatbed it back to his shop and take care of that and any fine tuning.

He seems to be quite knowledgeable. He was talking to me for about 30 min of some of the engines they did. Some back in the 70's where they were breaking all kinds of records (Some of these were in boats also) Getting over 9000 RPM out of a big block.

So far I have my Edelbrock Performer RPM Air-Gap (http://store.summitracing.com/partdetail.asp?part=EDL%2D7561&FROM=MG) intake. Ordering these Stainless steels valves (http://www.competitionproducts.com/prodinfo.asp?number=8455)

Was getting this Lunati 60203 (http://store.summitracing.com/partdetail.asp?part=LUN%2D60203&FROM=MG) cam and these Crane springs and retainers (http://store.summitracing.com/partdetail.asp?part=CRN%2D13308%2D1&FROM=MG)
along with the Keith Black hypereutectic pistons (http://store.summitracing.com/partdetail.asp?part=UEM%2DKB160030%2D8&FROM=MG). He said cast should be fine for my application. Just street. No idea what the CR is gonna be though. Any guesses? He said the cam should be ok, maybe a little rough. He was telling me about a cam he once used in his top fuel dragster that was close to a full inch lift! (.9 something) I think this was back in the 70's

Sealed Power rings (http://store.summitracing.com/partdetail.asp?part=SLP-E-243K030) and rod and main bearings, oh, and a gasket set. Any recommendations on bearings and gasket set? Also, is there anything wrong with the combo of items I listed above? I'd like to order this stuff and get it to him, even though he said it might be like a month until he can start building it

I'm open to any and all suggestions. I want to do this right the first time

hotrodrobert
Jan 2nd, 08, 4:37 PM
That is not a big cam. It should be a decent ride-a-round piece, though.
Keith Black only lists one piston for the 402. It has a -17cc .180" dome and with 119cc heads (most likely for 049 stock heads) the compression ratio is 8.5 according to the KB catalogue. That does not include overbore, but it is close.
If you angle mill those heads .100" and install 2.19" intake valves, the CR will be mid to high 9's, which is what I would want on a driver:yes:
Be SURE your machinist knows how and has the equiptment to properly angle mill the heads.

FlameOut
Jan 2nd, 08, 9:18 PM
I'll mention the angle milling of the heads to him. He had mentioned milling, but don't remember the word 'angle' in there. As for the 2.19" intake valves, where can I find them? I found the valves I thought I needed on the Competition Products (http://www.competitionproducts.com/prodinfo.asp?number=8455) site, but there is no mention of size, and searching their site, couldn't find anything else

reading through another post (amazing the stuff you find with the search button), I found a mention of the Keith Black KB-160 for a .030 over 402, so I guess that is the ones I referenced on the Summit site (KB160030 (http://store.summitracing.com/partdetail.asp?part=UEM%2DKB160030%2D8&FROM=MG))

Hate having to keep asking all of these question, but I just want to be 100% sure I'm ordering the correct parts.

edit: I did find the 2.19 valves on the site, is this (http://www.competitionproducts.com/prodinfo.asp?number=2190CP1) what I need then? Just get 8 of those then 8 stock exhaust valves?

mr 4 speed
Jan 3rd, 08, 2:21 AM
Bill,you'll be fine with the 2.06/1.72 valves for your combo.The link I sent you from Competition Products are for the 2.06/1.72
I had a 396 that ran mid 12's and it was nothing more than a stock 325 HP motor with a 240/246 @.050 Crower solid lifter cam.

Tom Mobley
Jan 3rd, 08, 3:21 AM
watch out for those 70s guys running loose bearing clearances and High Volume/High Pressure oil pump. You don't want either of those.

mr 4 speed
Jan 3rd, 08, 10:15 AM
watch out for those 70s guys running loose bearing clearances and High Volume/High Pressure oil pump. You don't want either of those.

yup..along with the grooved bearings. I have heard those 1" lift cam stories before too :)