Thread: rebuilding 402 need some advice

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I was wanting to know what engine kits are good quality and will not hurt the pocket book to much, and what brands should i stay away from or what brands do you reccomend for gaskets, bearings, pistons, rings. Also would like some ideas on a cam thats not to radicle. I would like to increase some power but changing the heads right now are out of the question at this moment. Any sugestions greatly appreciated

My engine is a 72 chevy 402 going to be bored 30 over
Heads are stock open chamber
Piston are stock 402 open chamber style

First off, welcome to CHR! We've got a number of really 1st rate engine guys on here so you should get lots of advice and all your questions answered! First off, is the machine work all done, or still needs a final hone to fit the pistons? As for the cam, most everyone is going hydraulic roller these days because of the additives that are no longer allowed to be put in the oil, zinc mainly.....More money, but if it's a project you're keeping it's probably well worth the extra $$$$$.....

Good having you here, hang on and the bbc guys will be around to give you some ideas, I'm sure!

First off i like to say thank you for responding to my post. To answer your question i just took it to the machine shop yesterday. Just wished i had more money to dump into it i have dreamed of this day to build this engine since i was 14. I just got the truck for my birthday from my father in january. Roller cams do sound nice

From what I've seen and heard on using the hydraulic roller cams, it's almost a necessity these days!!! Using a flat tappet cam anymore seems to be like playing Russian Roulette, seems a lot of the flat tappet cams lose a lobe or two within a couple thousand miles......

Welcome to CHR!
I like the 402 motor – great truck motivator and they can be built on a reasonable budget. I would champion what Dave said, re; roller cam. The 402 was originally a flat tappet design so you’ll need to be careful on the selection of aftermarket lifters. The Comp Cams roller replacement part number 854-16 works in the 402. They’re dear ($425), but they’re a quality item. Pat McCarthy will probably chime in with other suggestions as this is what he does for a living! A note of caution here – because the roller lifters are taller, you will need shorter push rods if you stay with the stock heads.

There’s a whole bunch of roller cams that will work. Tell us what you’d like to achieve and give some detail on which truck you working on, rear end ratio, tire size, auto or manual transmission?

Lots of knowledge here and we love to help!

Regards,
Glenn

use a later model block set up for oem lifters and sell your 72 block/crank to someone with a 396 car

At this point it has a th400 stock, the rear end is stock, and stock rims with 235/75/15. I woul like to hop it up a little between 300-400 hp would of liked more but tight on money. It is desapointing something that big only around 270 hp. Why should i get another block. Also what kits are good with good quality and a good price, and which ones should i stay away from

On an almost stock build such as you're planning (and keeping your budget in mind) you might want to look at some of the Federal Mogul overhaul kits. Used to use them in the past before all the stroker kits and the like came out. Never had any problems with them, at the level of power you're looking for I would think Federal Mogul or Sealed Power would be adequate.

It would be great if you could get us some numbers from the block and the heads. I’m thinking that the pad on the front of the engine will have “TK” followed by a B, M, W, or X. The casting number for your heads will help a bit as well. Even though you indicated you want to keep the stock heads, you’ll need to have them checked out and re-worked with at least a good valve job and new seals. The following head casting numbers are pretty common and you probably have one of these three:

3993820, 1971-1984 oval port open chamber 402 and 454 – 113cc chambers
3999241, 1972 oval port open chamber 402 and 454 – 113cc chambers
6272292- 1970-1978 oval port open chamber -113 cc chambers

I know you said you’re on a “budget” – but you didn’t say how big the budget is. As Jerry mentioned, you could off the block on eBay for probably somewhere in the $300 - $600 and start fresh. You could have Pat build you a sweet engine – and know that you’ve got one of the best, or you can build this one yourself and learn a lot as you go! I’m old enough to be you dad (maybe grandfather) and I still like to “do-it-myself” however; I have learned that there are some things that are best done by professionals! While your engine is at the machine shop, buy a couple good books on big block Chevy engines and study them very carefully – there will be a test!

Machine shop is the first stop – have them inspect the block (sounds like this may already be underway) and perform the following:

1. Bore .030 over

2. Deck the block to make is nice and square

3. Line bore mains

4. Check the crank – turn .010 as necessary

5. Insert new cam bearings

6. Install all new freeze plugs (brass) and get all new threaded plugs. Have the machinist show you where they all are so you can make sure they’re installed as you put things back together.

7. Have you machinist check your rods, re-size as necessary and put in new ARP bolts. These bolts cost about $125 but are money well spent.

8. Have your machinist put your new pistons on the rods – KB160 series are fine for your build ($375 set). 1.765 compression height .180 dome with the stock 6.135 rods and stock 3.76 crank should get you in the 9.5:1ish area (after heads are surfaced) – use a .022 head gasket.

9. Buy your rings, bearings and gaskets from the machine shop. This helps to make sure you get the right ones! If you haven’t installed piston rings before, ask for help here – the machinist can put them on for you or he/she will show you how.

10. Have your heads done here too – If you can afford to go the roller cam route, go with a kit from Comp Cams – K11-413-8. This kit has the cam, lifters, springs, seals, retainers and locks. Your machinist can do a valve job, surface the heads and assemble with these new parts. The kit is about a $1,000. You also need the rocker arm kit that includes new roller tip rockers (1.72) as well as new balls, nuts and most importantly new pushrods that accommodate the roller lifters. This adds another $200 - but if you go the roller route it's critical to have the correct geometry here or you will ruin thing in a New York minute!

Now you get to take all this stuff home and put it together! Be sure and scrub the block with hot soapy water and dry with compressed air. Get a good engine stand – Harbor Freight or similar. Once the block is spotlessly clean – paint it with good engine enamel.

Go slow and ask lots of questions. If you don’t have all the tools you need, buy or borrow them. Torque wrench is a must as is a piston ring compressor, a good set of sockets and flat wrenches.

Up top, I’d use a Performer RPM and good ol’ 750 CFM Quadrajet.

Finish off with some good ceramic coated Hooker headers and you have 400 plus on tap!

I know this is a lot to digest – hopefully Pat will chime in as he really is the big block master. Listen to anything he tells you as he’s built fifty(or more!) to every -one I’ve built and like I said – he makes his living doing this while I just enjoy building one “now-and-again”..

Regards,
Glenn

i can not add to much but i deal with warehouse.s and a dealer for many parts so i get what i like to use when i am building a engine not just machining it .that parts you should stay away from ? for this build most name brand parts are fine . on the cam ....roller is the only way and there many ways to go here .i do not use much of comp cam stuff . the roller lifters are only made by a few lifter companys so there alot of rebox sometimes at ends up to who.s sticker you like more in the box lifter.s. in many case.s . but there no easy way out on pushrods you buy a kit use another brand of roller rockers . your pushrod can be wrong . i never buy cam KITS with push rods less a bone stock engine . i only buy push rods that fit the engine at time of build as to what real push rod it needs .this is done by checking the pushrod length one way is a mild lift check .i do all engine i build less it,s a bone stock build . like jerry said you could be better off in the long run with a 454 mark 6 roller block? sell the 402 but you did not ask that .your old 402 may have value to some one looking to build a number .s matched 402 but still many 396/402s out there. your.s is a low out put engine and the mark 6 454 still fits in many newer trucks so the core price is much more on the 454 and the cost of the new gasket kit is more on the 454 mark 6 so in the long run a 454 would be one way to go it will not be less money .i built many of both engines. machine work needs to be right you want the block tru deck . if your shop can do that you want the piston at 0 deck to .010 in the hole this has some what to do with head gaskets on how thick .039 to.050+ they are.keep away from a old tin steel shim Gm gasket there many head gaskets.there are better then them . many are grafoiled coated or blue perma torque FELpros used 100s of them over the years work very well if the finish is good on heads and block deck .the fast way to build CID with is engine is by using a 454 crank 4.000 and KB sells a piston for the swap get it to around 427 this may be one way to go if your crank needs work

If I was building a chev BBC, I wouldn't use any 396,402,427 cranks these days because there isn't much choice in pistons of those ch------------(based on stock/low hp, street engines)

The 454 core stuff is much more available and the parts supply is unlimited-----(I think I am down to only 5 more 454 mark 4 blocks)

For a street engine today, you can pay for a roller set up or you can replace what ever you build flat tappet next winter as you do it over---
I am about 30 or so engines in line here and I think they all are roller--except foe a couple fifties flatheads and a Ford Y-block

Pat--is all the snow melted?????????

Originally Posted by jerry clayton

If I was building a chev BBC, I wouldn't use any 396,402,427 cranks these days because there isn't much choice in pistons of those ch------------(based on stock/low hp, street engines)

The 454 core stuff is much more available and the parts supply is unlimited-----(I think I am down to only 5 more 454 mark 4 blocks)

For a street engine today, you can pay for a roller set up or you can replace what ever you build flat tappet next winter as you do it over---
I am about 30 or so engines in line here and I think they all are roller--except foe a couple fifties flatheads and a Ford Y-block

Pat--is all the snow melted?????????

yep as for the 454 mark 4 cores . i have many only one 454 mark 6 long block but there not as cheap as a 454 mark 4 core .the mark 5 s would have to be just about free for me to buy any . the last 30 engine i built all were rollers . i have so many going together i realy never take time to count them jerry but i have this spring.460.489.496.498.502.510.540.548.582..598s the 598 i am building 4 .ones done all machine work finished on 2 of the 598 and better then 3/4 of this list is done. i really do not know how manys cars i ever painted or how many bbc i built but .i done many .i been getting custom pistons made by one company so i can get any CH they built me 3 sets so far so good . price is very good quality is very nice . so not using much speed pros or other pistons in the lower buck forged line. when i can now buy a set for the same price and have them built my way for ring size . ring pack. pin size . and pin locks . and most any CR and CH . i may just build that honda rod or sbc rod journal 4.500 crank 4.165 bore 402 with 927 wrist pins with .043 rings steel top with a napier# 2 oil 3mm and show the LS guys how to make some steam with a old bbc red headed step child 396/402 .it would be nothing for me to build this short block it may take me longer on head s there so many to pick from . but the new dart o ports i am thinking . i going to start getting parts for this thing . first is find a good /cheap 396 block.i have to pull that one off the chain my freind has for a boat anchor

sorry for the long delay to get back to you all i have been pulling doubles all week to pay for engine, the only numbers i have at this point are the heads # 6272992 looked at them before i had taken them off. I will get the block# hopefully tomorrow, because of all the doubles they a closed when i get off and when I go to work. They already started on the machine work on the block and crank so at this point going to keep those, My father already had the heads worked on. budget right now looking like a $1000 to $2000. Machine work cost me $300. just want a little bit more power without loosing an arm and leg. down the road I will buy a block and build it from ground up but first need to save money for that, and get this truck at least depandable with a little more power, after i do that then i got to pull the engine out of my 300zx twin turbo to do some repairs as well and that is going to cost me alot. again thank you all for the advice and tips. Just trying to figure out what path I want to take, And I just do not know all the good parts for these old chevy's. But i do know my motorcycles, and more upto date vehicles

As mentioned before, I've used the Sealed Power engine kits and been pleased with them. Lots of us on here understand the "build what I got" philosophy, and having to wait and save up some $$$$$ to build the engine (or car, or suspension, or drivetrain, or whatever) that we really want! When making suggestions it's always easier to spend someone else's money then to spend your own!!!!

No way a 402 would ever be the ultimate bbc to build, but it can certainly be built into a solid and reliable engine that produces a respectable amount of horsepower without breaking the bank!!!!

Northern Auto Parts has some nice complete rebuild kits for good prices. I've done several engines with their stuff and had good results.