Topic: Rebuild Ideas

[Kevin]

I've got a Pontiac 400 W72 from '77. The block checked out ok, no cracks etc, but the heads are bad. I'm pretty sure I've located a set that I'm willing to get, but that's a different story.

I have a previous post on the general section of the forum about engine build recommendations, but I thought I'd post up here since this is the proper section, and where all the experts post. So here we go..

Block 1977 Pontiac W72 400 Casting 557 (Weaker Block)

Going with a .30 over bore So correct my parts ideas according to that bore.

Crank - Sticking with stock crank. Going to have it turned etc.

Cam - Recommended to the XE262H Comp Cams model by Jim Lehart
        = Going to go with this kit here http://www.summitracing.com/parts/CCA-K51-222-4/

Heads - Not sure, looking into #62 Heads now.

Bolts - Getting the ARP Engine Bolt Kit
        =  ARP KIT http://www.summitracing.com/parts/ARP-594-9701/
        - Alternator Bracket Bolt Kit
        = http://www.summitracing.com/parts/ARP-490-3302/

Main Bearings - Clevite P Series Main Bearings
                     = http://www.summitracing.com/parts/CLE-MS496P30/

Cam Bearings - Clevite P Series Rod Bearings    
                     = http://www.summitracing.com/parts/CLE-CB758P30/?rtype=10

Cam Bolt Kit = ARP Cam Bolt Kit
                   =  http://www.summitracing.com/parts/ARP-190-1001/

Pistons - Speed Pro Pistons  Also do I need the flat top or the dome?
           = http://www.summitracing.com/parts/TRW-L2262F/

Connecting Rods = Probably TRW from Jim Lehart

Head Parts = Probably all from Jim Lehart when the time comes

Rocker Arms = Comp Cams Magnum Roller Tip (Also, what ratio and what measurements?)

Lifters = Comp Cams Pro Magnum Hydraulic Lifters
          = http://www.summitracing.com/parts/CCA-863-16/

Timing Set = Comp Cams Magnum Double Roller Set
                 = http://www.summitracing.com/parts/CCA-2112/

Head Gaskets = Fel Pro

Intake =  Stock

Intake Gasket - Fel Pro
                      =  http://www.summitracing.com/parts/FPP-1233/  

Carb = Quadrajet from a 455 Pontiac. Needs Rebuild, Cliff Ruggles or Maryland Bandit or Jim Lehart..

Freeze Plugs - Sealed Power Brass Freeze Plugs
                   = http://www.summitracing.com/parts/SLP-381-8021/

[80ws6ta]

All of that looks great! I was going to build my '68 400 like that, but I was going to use some 6x-4's. Then I found out I had a 455 sitting in another car of mine so (needless to say) I decided to go with it instead! I had considered using some 62's as well, but then I asked Jim about it and we both agreed that it would be way too much compression. 6X-4's can be milled pretty easy to get the 9.5:1 compression you need. Those 62's are good heads, but they are just too much. Everything else looks great! Good luck with it all and I hope it goes well for you!

[Kevin]

Am I leaving anything out? What kind of Head Gaskets? How many cam bearings do I need? What about for the intake, anything else I need for that?

As far as the heads being too much compression, can't I use different pistons to work with those heads? I mean, can't I just have head work done on these heads to make it work?

[4SPEED]

I will scan all my paper work from my 400 build and send it to ya.

[Rick]

As far as the heads being too much compression, can't I use different pistons to work with those heads? I mean, can't I just have head work done on these heads to make it work?

By doing a little smoothing on the combustion chambers, you will pick up a few CCs of end volume, which helps with the static compression ratio (SCR).  Still those are small-chamber heads intended for high compressions so that's still not going to get you where you want to be.  Milling the heads only raises the SCR.  You definitely do NOT want domed pistons -- instead, you want flat top pistons and if you are sticking with the 62 heads (decent heads with large exhaust valves, BTW) you want the tops of those pistons mildly "dished" to create even more end volume.

How much dish?  You need to CC the heads you have in hand to determine their ACTUAL volume.  The tables you find in the reference material only give the "nominal", or DESIGN volumes.  These heads were all machined on equipment that was run by humans, not computers.  The machines were set-up by technicians for the specified volume, and then operators would just run them.  The operators didn't do any real QC on the product they turned out, so whatever came off the machine is what you got.  It's typical for those machines to start "wandering" (generally going larger) until somebody caught them, and then sending the set-up man back around to adjust them.  The bottom line is that you can only approximate the combustion chamber volumes by the tables of casting numbers -- you have to MEASURE them yourself to know for sure what you actually have.  Once you do that, then just run the compression ratio calculations and find out what "dish" volume you want on the pistons.

Mr. P-body will be along shortly to enlighten us on how much dish you can put in the pistons you want to use.

[Kevin]

I will scan all my paper work from my 400 build and send it to ya.

Ok cool. I mean, my build isn't going to be nearly as expensive as yours I bet, but it will surely help!! Thanks a lot.
I've been trying talk to as many people as possible about all this stuff, and I appreciate all the input I can get...

I've now heard it both ways,
Answer 1) the #62 will be fine ( get me to 9.5:1 compression)
Answer 2) The #62 is too much compression for my engine, and I should Not use it..

I need a definitive answer, not trying to be rude at all!  
Also, thanks a lot Rick, do you recommend I get the #62 or something else?

I plan on running 93 octane gas anyway, so I'm just trying to figure it all out as to what fits my needs..

[4SPEED]

I used 6x8's and have 9.5 to 1. if I would have went with dome pistons ,it would of been 9to 1  but my ta sounds like a race car and glad I didn't spend another 300 on domed pistons. instead of a more stock sound like I wanted.

a stock piston is all you will need,  the high dollar aluminum stuff is is for race cars. not  a performance stock.  any body that has them is racing there car or just likes to tell you how they spent 600 to 900 for pistons.  aluminum is to dissipate the heat of super chargers, blowers and NOS. that all its for.

the motor builder will take care of the bearings. as for what size it will need.

zero decked the block, milled the heads .045 to 90.0 cc's , milled intake side of the head to fit the intake

[Rick]

Also, thanks a lot Rick, do you recommend I get the #62 or something else?

The 62s are good heads, but you need to watch the SCR in order to be able to run on the 93 octane fuel that's available today.  The plus side of the 62s is that they already have the 1.77" exhaust valves, but you have to have those added to 6Xs if you elect to use those.  It's generally accepted that you don't want to run higher than 9.25:1 (with cast iron heads) or so to stay out of trouble on pump gas.

Nothing sucks worse than needing special high octane fuel to keep your engine running, then getting low on gas in East Bumruck.

[Kevin]

So I could use #62, but I'd have to have some modification done to them or my pistons to achieve a lower SCR for street use? That's basically the idea, right?

[4SPEED]

[Rick]

So I could use #62, but I'd have to have some modification done to them or my pistons to achieve a lower SCR for street use? That's basically the idea, right?

Right.  You need to add unswept or "end" volume somewhere.  That can be done by modifying the combustion chamber along the lines laid out in Jim Hand's book on Pontiac V8s, and/or by modifying the tops of the pistons by having a shallow "dish" or depression milled into them.  Most likely you will end up with a combination of the two.  Dishing the piston isn't hard for a competent machine shop to do.

[Kevin]

So I could use #62, but I'd have to have some modification done to them or my pistons to achieve a lower SCR for street use? That's basically the idea, right?

Right.  You need to add unswept or "end" volume somewhere.  That can be done by modifying the combustion chamber along the lines laid out in Jim Hand's book on Pontiac V8s, and/or by modifying the tops of the pistons by having a shallow "dish" or depression milled into them.  Most likely you will end up with a combination of the two.  Dishing the piston isn't hard for a competent machine shop to do.

Ok, good deal. Thanks Rick!



Thanks to Doug also for that! Is my list looking pretty good so far? Is there anything that I need to add?

Also, what about head gaskets? I've heard that Fel Pro is the best, not to mention I saw that on Doug's invoice, must be the best choice...
Anything else I'm missing here? I'm going to get my valves from Jim Lehart, but I think I've got everything pretty well laid out so far. Let me know please!

Thanks Doug and Rick, really helps me out!

So basically I should wait on the bearings and let the machine shop figure that out? I'm not going to 'order' anything for a little while, but of course all of this can be subject to change when I talk to my machinist tomorrow... I've got to get my intake and all my other parts to him as well.

I was also going to buy ALL new bolts, I assume this is the best route? Also, is reusing your old oil pan a bad idea, or does it just depend?

[4SPEED]

fel pro and your choice on the oil pan.mine looked like new after it was cleaned.  ( no rust pits )

if the bolt is pitted up at the head get new ones. these dont stretch. 

[Kevin]

fel pro and your choice on the oil pan.mine looked like new after it was cleaned.  ( no rust pits )

if the bolt is pitted up at the head get new ones. these dont stretch. 

Ok, thanks a lot! I'm using the summit racing wishlist feature and adding everything in there as I go, to help keep track..

[4SPEED]

on mine I told him what I wanted and paid a down payment. and let him order the parts so the parts are under his warranty. and not on me.  his parts, his work. his warranty.  I didn't want any problems with it down the road.

like my coolant leek I have.  I made a phone call, he said no problem I'll fix it.