'67 400 build
 

First post so take it easy on me.
Hi All, I've been searching the forum a lot but haven't quite found the answers I was looking for so I'll ask.
Time to rebuild the 67 400 in my GTO.
Last time it was rebuilt was '93 and things have changed a lot since then.

Here is what I want out of it.
Good street manners, It is just gonna be a cruiser, probably never going to the strip. Probably won't see anything over 5000 RPM. Just smoking the tires here and there. Want it to run on 93 octane and not get hot. I would like a little lope in the idle so it sounds like a muscle car. If it shakes some at idle that is OK too.

Here is what I have.
69 GTO, M20, 3.90 posi.
67 GP 400, 670 heads, Edelbrock performer manifold and 2157 cam, Qjet, HEI, Hooker headers. Cylinders are .030 over now, it remains to be seen if it need to be bored again. Crap pistons, they are going no matter what. (Double dish, 8 valve relief, big bevel around the crown, low deck height, cast pistons from the '80's)

Questions: Since the 67 oil pan, windage tray, valley cover and timing cover are different than later years should I keep what I have or find newer parts? Any advantages?
From searching I found that the Performer manifold can go, I found a 1972 cast iron manifold locally to replace it. It desn't sound like the 2157 cam is what I want either. Any recommendations?
Since I am replacing the pistons what should I look for? Do I really need forged for a cruiser engine? I want to stay close to 0 deck height to keep the squish tight and keep the heat and detonation down.
I could do some light home porting/ port matching with some guidance. I have the tools and I did some porting 20 years ago on chevys.

I used to be an engine machinist by trade (20 years ago) and I still know some guys with machine shops that will let me do whatever I want so machine work isn't a problem.
The budget is a problem though. I've had this GTO for over 30 years and it set the last 18 or so. It is in pretty bad shape and right now the body is off the frame and I do not have an unlimited budget. Everything on the car needs re done so I can't be dropping 3 grand on this engine, maybe I can do more on the next engine.

I haven't kept up with engine technology over the years and that is why I am asking here for opinions. Seems like there are some pretty sharp guys here.
Seems like not a whole lot of people using the 670 heads.

Reference Paul Carter's (gtofreek) build of a '67 400

I just finished reading that thread. He is going a lot further than I am with this project but I did get some good ideas from there. Thanks!


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Depending on the compression ratio.
I'd look at the Lunati Voodoo 10510702

Advertised Duration (Int/Exh): 262/268
Duration @ .050 (Int/Exh): 219/227
Gross Valve Lift (Int/Exh): .468/.489
LSA/ICL: 112/108

https://www.youtube.com/watch?v=eVTlTFTuS18


Next one up is the 10510703 . This would make peak power higher than you are likely to go.
https://www.youtube.com/watch?v=_-Lq3icJ2Vo

That is a stock type rebuild using all original 67 parts except for the roller cam/lifters (and pistons).

I'd keep the Oil Pan, the 8 bolt timing cover, all the pulleys and get a correct 67 water pump or get yours rebuilt properly (Flying Dutchman). This will make accessories and belts so much simpler. I'd spring and buy a $150.00 valley pan from SD or Butler.

I'd swap everything over to the '70-up timing cover, etc. The later parts are much easier to find.

There are no good cast pistons for a 400. The cheapest decent 400 pistons are the SP L2262F forged pistons. They sell for about $325 on Ebay, and about $400 or less, with moly rings. The pin height is advertised at 1.714. If you want to get near zero deck, without having to cut a lot off the decks, you can buy the Auto-Tec pistons, and they will give you more pin height, for no extra charge. At least that's what I was told. They are around $500.

You said you have a '69 GTO, with a 4-speed & 3.90 gears. That's what I had. It was an early '69 RA3. So, it had a 744 cam. It had a slight lope, but was very streetable. I put over 60k miles on it, then raced it for 2 seasons.

The Summit 2802 cam is similar to the 744 cam, but has more lift. It's also about as cheap as you'll find. So, it might be a good choice. The 2801 is the same price, but will idle fairly smooth in a 400.

BUT, the 670 heads may produce more compression than you want, for pump gas, if using flat top pistons. Icon makes a nice piston with a 14cc dish, & a 1.720 pin height.

http://www.cnc-motorsports.com/icon-...ore-48653.html

Unless you are really set on using those 670 heads, I'd go with a low compression build. Since you don't wanna rev past 5000, & are not looking to make max power, you don't even need big valves. Some #46 heads, with screw-in studs, off a '73-'74 350 will work. There are also the 5c-4 heads off an early '75 350, and the 6x-4 heads off late '75-'77 350's, & '77-'79 W-72 400's.

The 72 iron intake you have will work with these later heads. If you go with low compression, I'd go with a Voodoo cam, like maybe a 262.

http://www.lunatipower.com/Product.aspx?id=1775

Ideas & opinions on all Pontiac engine builds vary greatly, Depends on who you ask. Most seem to recommend high dollar max power builds. Like it's almost a sin to leave any power "on the table". But, if you just want an idle to 5000rpm pump gas street engine, you may not need the high end build.

But, to build one for under $3000, you'll need to do MOST of the machine & assembly work yourself.

Here's a crate motor recipe, similar to what I'd recommend. But, I'd upgrade to forged rods. Tho resized cast rods are plenty safe to your stated 5000 rpm limit.

http://lenwilliamsautomachine.com/400_Long_Block.html

Just thought of this. If you decide to use the 670 heads, and also have the know-how & correct machines, you can dish the SP forged pistons yourself, & save over $100. They are said to have plenty of meat, so that a decent dish can be safely cut. I think there are posts on this site, with pics, of an SP with a dish machined into it. I believe I read that it needs to be D-shaped. Maybe somebody can link to some good info on dishing the SP pistons.

http://forums.maxperformanceinc.com/...67&postcount=9

http://www.hotrodders.com/forum/dish...nglepost3.html

Thanks guys. This is the kind of info I am looking for. Keep it coming.


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You have the 670 heads, and for a few hundred dollars more cost over the shelf variety pistons you can step up to a set of Ross pistons from either Butler or Kaufman with a custom dish to put compression exactly where you want it. I personally think that getting the complete stroker kit from either of these two puts you money ahead despite the additional up-front costs. Assemblies come ready to drop in and balanced. By the time you pay to have your stock crank turned down and balanced you are about the same money as going new. Not only that but you go from around a 406 to a 462 for the same money. The additional cubes translate into low and mid-range torque to plant you back in the seat without going overboard on cam size.

Roller cams vs. flat tappet sort of falls into the "you can pay me now or pay me later" category. While it's true the HR is going to require an additional $600 up front, what's the price on a flat tappet cam going bad in a short time? That requires a new cam and lifters and the disassembly and complete cleaning of the engine with new bearings.

I like to stay under 9.3:1 with today's gas. If you retain the 400 at .030" over, and your heads cc out to 75cc's, then minimum piston dish is 16cc's. If your heads have had a couple mills and chambers are down to 72cc's, then your piston dish should be a minimum of 19cc's. The mild cam is going to have more dynamic compression, and it becomes more important to pick the proper pistons.

If you go to the 4.25" stroker kit and .030" over (4.150), then piston dish should be 29cc's with a 75cc chamber, and dish of 32cc's with a 72cc chamber.

We just completed a '67 WS engine for a friend that was built with a stroker kit from Butler and SD Performance worked 670 heads with 75cc chambers. Ross pistons special ordered from Butler were 29cc dish. Dave at SD also spec'd out a nice mild 224/230 cam on a 112 LSA for this build that should also be right what you are looking for if you decide to go with a HR setup. Just put a call into Dave at SD and see what he has to say. Engine was at 4.150" and had not been run yet, but had major problems from the ebay seller that required a fresh start. While there were many things wrong with the crate engine build, at least they did a fair job on the boring. We were able to have our local shop only hone another .005" for the new 4.155" spec pistons.

I went with the SP forged 2262 pistons, 5140 rods, #47 heads (69 350), and 10510703 Voodoo cam, and Comp 995 springs for my 400. I run the 702 Voodoo in my 350 and have no complaints.

You have 4 speed and plenty of gear, so I wouldn't be concerned with losing bottom end. You will have power out to higher rpm's than your intended use.

With either of those cams you will need to account for higher lift than stock heads can handle. That would include valve guides/seals to retainer clearance, and springs that won't coil bind. I run Crower 68404 springs with my 702 cam.

I've never heard anyone complain about the 2801 as a very good replacement street cam. Less than that seems to be not enough, and more than that starts getting into "what is my next weakest link" territory. Stock upgrade replacement springs like Comp 988's would go good with a 2801. I've heard of people running a stock valve train with 2801's, but it walks the edge of compatibility with stock stuff.

Since your only looking to rev to 5000 do not even bother to plug in the grinder but for gasket matching the Intake ports if they need such
Just note that even the 400 HO motor with its 068 Cam made peak HP at 4800, in reality your gonna be shifting at 5400 if you want to make use of what you have.

If you do any light grinding to those heads besides the Intake match you want to roll over the sharp lip of the combustion chamber where it hangs out from the cylinder.
This is best done with a sanding roll and of course before any Head milling that my be needed.

Also note that these closed chamber heads need very rich jetting once a certain level of Caming is reached, so be ready for that before you beat on it!

Start off on the fat side and go leaner by means of full throttle plug reading .
Do a search for " plug reading 101" and digest that into fully before you full throttle the new motor.

I caught the last line about your budget being less than 3 grand for the engine.

Only way you're going to contain cost on an engine build is to do the bare minimum. Do a ring and bearing job, swap in a Summit 2801 cam, valve job and knurl guides and let it ride. Anything else is going to cost the GDP of Brazil. Not every build has to be a fire-breathing stroker, especially if you're breaking the bank just to put the wheels back on it.

Forged pistons are 400, good rods are 350, head work is ridiculous. I run 670s and they're gonna need valves, seats, springs, retainers, seals, guides, etc etc if you do it "right". I'm building my 67 400/670 combo as a max-effort street/strip and its gonna cost a lot more than 3 grand. Yarf.

" I caught the last line about your budget being less than 3 grand for the engine..."


"... used to be an engine machinist by trade (20 years ago) and I still know some guys with machine shops that will let me do whatever I want so machine work isn't a problem.
The budget is a problem...I do not have an unlimited budget...I can't be dropping 3 grand on this engine..."


I've noticed that I, and many(most) others sometimes don't catch all the details of a guy's plan, before giving our opinions. So, I posted a quote of some of what the OP said. The 2 main points are: (1) The entire engine needs to cost less than $3k. (2) He can do the machine work himself, I assume for free, or real cheap.

I assume that means he can do the crank, all the block work, and a complete valve job. If not, maybe he can tell us exactly what he can & can't do.

One example of where he could save some $$, is by resizing the cast rods himself. That would limit their cost, to the price of the ARP rod bolts. The resized rods are plenty good up to well past the rpm limit he's set for this engine.

If he can machine the decks, and dish the SP pistons, that will save $$$ over custom pistons.

http://www.ebay.com/itm/Speed-Pro-TR...RWvhp2&vxp=mtr

And many have posted about spending $800 or so on iron heads. But, if he can do all the machine work, that will limit his cost to parts only.

Yeah, I can do the block, crank, rods and heads myself for the cost of parts and I realize now that it is probably going to turn out to be a re-ring and bearing job, Turned crank, resized rods with new bolts, same crappy pistons (if possible), I can deck the block to help the squish as long as I make sure not to deck it so much as to go past 0 deck with a 1.714 pin height. Need to measure what I have now.
The heads were done 20 years ago with all new guides, seats, bowl job, valves and springs. They just need a touch up valve job and maybe a little time with the die grinder to get out the casting flash and port match to the intake. There is only 3 or 4 miles (but 20 years) on the heads since that work was done.
I'll then mock it up and CC everything and figure out what my SCR is and pick a cam from there.
Of course all this depends on what the Magnaflux says. This stuff may all be cracked.
I'll keep the headers just because I already own them. I would rather have RARE or Pypes manifolds but that is un-necessary at this point and then requires all new exhaust to the axles. I will just live with the clucth linkage and oil filter clearance and try not to bang the headers on the road too much.

Still there is a lot of good advice in this thread I can reference later and others may benefit from if they are doing a budget build with 670's.
Maybe I will stumble on to some different heads at one of the machine shops and if so some L2262F's aren't out of the question.
I need to get it torn down this weekend and see what I really have to work with. I just have the heads off right now.

I just want to get the car back to a driver for now, it has set too long as it is.
I't will probably be primered with 2 front seats and no interior for now. Finished as funds allow. Frame is out and being straightened, then blasted and painted and reassembled with all new suspension bushings. Clutch needs replaced, Muncie and diff are OK... I think. I' will look at them too. Good thing I can do all of this myself, saves a ton on labor and I like doing it too.

I have a long way to go with this car and this engine will be a budget job for now. Of course I would rather build a roller cam, stroker with aluminum heads but that will have to wait until later. The engine is easy enough to pull out and do later when funds allow.

"...I can deck the block to help the squish as long as I make sure not to deck it so much as to go past 0 deck with a 1.714 pin height..."

If you reuse your pistons, they only have a 1.700 pin height.

https://www.summitracing.com/parts/s...w/make/pontiac

And, resizing the rods might lower the piston in the cyl, slightly. So, it could take quite a bit off the decks to achieve zero deck height, with those pistons.

It has also been said that those pistons encourage detonation.

So, the $320 for forged pistons, might be a good investment, even for a low budget build.

http://www.ebay.com/itm/Speed-Pro-TR...JWvhoN&vxp=mtr

Those look like the pistons I have. Problem is that if I get the pistons you linked to my compression will be pretty high for pump gas. I will have to check and see if I can dish them or not. Depends on what machines are available at the shops. Or different heads.
Keep the ideas coming. I haven't bought anything yet so the plan is still open.
I won't be able to get any magnafluxing done until next week and then I will know what I am working with.

"...Problem is that if I get the pistons you linked to my compression will be pretty high for pump gas..."

"...I could do some light home porting/ port matching with some guidance. I have the tools and I did some porting 20 years ago on chevys..."

I've read of some opening up the chambers of the 670 heads. If you can take enuff out, that might solve your compression problem. Maybe somebody can post a link to this info.

http://forums.maxperformanceinc.com/...=670+head+mods

http://forums.maxperformanceinc.com/...7&postcount=23

http://forums.maxperformanceinc.com/...=670+head+mods

Even if you can't dish the pistons, you can remove some material just by smoothing off all the sharp edges of the valve reliefs. Not sure how many CC's can be removed that way. I assume it is limited only by how much material you remove, with your grinder.

I think I know a guy with a Bridgeport I can use. I'll check with him if/when I get to that point. One of the guys somewhere on this forum said there was plenty of meat to remove on top of those pistons to create a dish.

Do you still have the engine in the car and is it complete now?

Why not see if it will run as is?

I had a bunch of used up parts from a 400. Standard block, pistons and rods & a old set of 96 heads. I had a used cam and lifters. Bought new bearings, rings, timing chain & gears and a gasket set.
The High School Vo Tech (my buddy is the teacher) kids had a blast slapping it together.
That was 5 years ago. They used it to mock up my 84 T/A Chevy to Pontiac engine. It still runs great, no smoke, good compression. I think I have $400 bucks in it. It's out again and it's gonna get the carb rebuilt and a paint job. I'm gonna use it in another project this summer........

Naw. It's out of the car and partially disassembled. The rest of the car is in a million pieces too. The intake valves had some rust on the faces when I looked down the ports. I knew it was coming apart then.
Just running as it was? That was my intention at first. I was just going to get it running and try to get the body finished and an interior in it. Then I seen the coolant was low started taking things apart and found a lot of other problems I had forgot about.
I'm glad I disassembled the entire car so I can fix all the stuff I forgot was wrong with it but it really put the whammy on my engine budget.
I just need to be careful and do the things right that can't be fixed easily later while just squeaking by on the stuff that can be easily fixed later. Engines aren't hard to pull and re-do when more cash is available.
I wish I had 30K to do this with so I could just do it right the first time. If I could just win that darn PowerBall!!

Those 670s typically have 76-79 CC chambers. Don't believe the 72CC chamber data in the books, it's wrong. Mine CC'd at 76CCs after being milled about .015".

You can take those TRW forged flattop slugs and turn a round dish in them to lower compression with the 670s. Use some good moly rings and you'll be in good shape.