Went out this evening, was able to get the crank to lift on both ends (engine upside down) and very slightly turn using the nut for the balancer. Naturally, it seems to still be stuck due to the 2 pistons that I cannot get to the rod bolts. The next plan is to slowly soak all pistons and remove them leaving only the 2 that are still bolted in, and the 1 that has the crank in the wall.

I'm really hoping I can get it torn down by Saturday so I can get it out of the middle of the floor, for when the car arrives, but I also don't want to rush it and create more work or expense in the process.

Also, it's quite the task trying to position to pound out cylinders with the crank still in the way.

 

Supercars Unlimited has .030, .040,& .060 over pistons. Nothing in the description as to whether they are cast or forged. They look cast.

 

I had to post after post #80 to get to page 3, don't mind me. Just trying to follow along...

 

I’ve been stumbling through a 400G build over the past several months. In retrospect, I would highly recommend having block sonic tested (after having it mag’ed) to see it can bored to at least 4.000” bore size. That opens the door to piston and rod options. I mistakenly dismissed advice to sonic check block and instead I bored to 3.905 since there were a lot of ring options (its a common chevy bore size). But that then dictated custom forged pistons. Then the Eagle rods (that I assumed could be used with either 455 or 400G) did not physically fit down into the small 3.905 bore so i had to rebuild the stock rods. I should have taken the advice I was given early on from folks and strive for a 4” bore if at all possible.

 

Keep up the good work. I am happy to hear that you are keeping the original engine and will be re-installing.

 

Well..they're all out. Gonna need a couple pistons after all, but the bores actually look pretty good considering how they looked when pulling the heads off.

Now, next step is the machine shop to see if there's any more damage or if a cleaning (and one sleeve) is it. Still kinda torn on potentially boring it out since I'm already there, but I know I've got a lot to learn still.

 

You got them out; fantastic!! Fingers crossed on the block condition...

 

As far as what's visible, I'm feeling pretty good about it..but then again, I know there's a lot more to it.

I'm gonna probably give it a week or two to start combing through the car when it gets home, then go ahead and drop the block off (probably heads as well). When I spoke to the machine shop, they said they had a 6 week lead time on work being done, but if I'm going to need to do a lot more to the car than anticipated, I may hold off for a bit and continue to research and prepare.

 

Nice!! Congrats!

 

I was told two weeks to month when I dropped off my block, 4 months ago. Glad it is better than you thought, it sounds like a good car overall.

 

Well, block and heads will be going in this week. I'm hoping for the best (sleeve the 1 cylinder, general cleaning for everything else) on the block, but the heads are still a bit of a question.

First, I'm hoping they can get the rust out of the ports, and everything is still solid. If they are, as far as I'm aware I'll just need to have hardened seats installed to run unleaded (premium). Is this accurate? Also, is there anything else worth doing, knowing it's going to be a Day2 build (mild cam only)

I'd love to throw the house at block and heads, but at the end of the day, it's not going to be a race car..so it's not worth it for me

 

....and they're off. I was given a 6 week lead time, so we'll see in 6 weeks what the news will be.

IF everything checks out, and I don't need to bore it..has anyone used the rebuild kit from Supercars Unlimited? As much as I want to build this out to make a bit more power and all the things, I think I'd rather just play it safe and return it back to factory spec. I'll probably put an aftermarket intake and carb on it (unless it'd be cheaper to clean the factory intake) but that'd be the extent of what I do.

 

No reputable machine shop is going to touch that unless they bore it

 

Why do you say that? Obviously where the crack is will need bored for the sleeve, but if everything else is solid and can be cleaned up without boring..you're saying they'd just go ahead and bore it anyway?

 

It will need bored, any rust guarantees an overbore.. I sent in a nice looking 350 block with no ridge to possibly hone to 4.065". They said a couple of cylinders would not clean up properly, I went to 4.100" the next size in a modern piston. The 400G was basically to use 455 tooling and keep it at 400 ci. A 4" bore is still under square, go the maximum bore with some leeway incase of a future build.

 

Have the block checked for any other cracks.

 

Yeah, it's going in for sleeve/cleaning/magnaflux.

If it needs bored, so be it. I've never sent a block off that needed bored, yet had a bit of rust in the bores..but that being said I wouldn't be surprised if this one needed it. I know if it does, it's going to kill my budget for a while..but whatever it takes to save the original block.

 

Not to **** in your Cheerios but if $200-$300 for boring and decking (they'll have to deck it too) is going to kill your budget for a while you better save your money..... Welcome to the world of Oldsmobiles...

I paid $3600 for a stock 455 rebuild 15 years ago. Boring and decking was peanuts in the whole scheme of things.

Comparatively, a belly button SBC 5.7 for my boat was $1800.....the same guy did my 5.7 and 455

 

I came from Mopars, it's nothing new.

That being said, I figured boring would be more than that..but at the same time I've never had to price pistons/rods/etc. Quick looking, it's gonna add up quick. Especially when I'm hoping I don't need to spend it..ha.

 

Might as well dig this back up to the top-I've got less than a week until the "lead time" is up.

I've pretty much emotionally prepared (read:accepted the credit card bill coming up) for this needing bored out. Seeing as I've never dealt with anything other than stock internals (never even needed to buy pistons) am I going to need the crank rebalanced? Just trying to get a feel as the anticipation is kllling me..ha. In the grand scheme of things, I'm considering just having the shop build the engine there. I'd like to put a bit of cam into it, but beyond that nothing too major.

As far as intakes go, do the 400's share the same intake as a 455? IF the stock intake can't be cleaned up/saved, or it just makes more sense for me/them to buy an aftermarket intake, am I okay going after a 455 intake?

I know I have more decisions that are contingent upon what they say as far as the bore (such as which cam, what size carb, etc) but hopefully the ball can get rolling sooner than later.

 

The only meaningful difference between the G-block 400 and the 455 is the bore. Everything else is the same. The same manifold was used on both. The same heads were used on both. Rods, crank, oil pump, pan, cam, timing set, front cover, distributor, etc, etc are all the same.

Rebalancing is always prudent when swapping pistons. Is it mandatory? No.

 

Interesting..are port sizes the same for the intakes? I don't want to keep comparing things to Mopars, but that's what I'm experienced in. The 3 major SBM bolted up the same, but 1 had a different size port so it wasn't advised unless absolutely necessary.

 

They used the same intake. Same casting number, same part number.

The only thing comparable to Mopar is the fact that the Chrysler crank socket fits my Olds motors.

 

Good to know, ha. Thanks.

 

Forgot to update this...

Called last week, moreso to both low key do a status check as well as talk about just building it there. He said it's currently setup for the sleeve and checking the other cylinders in regards to possible boring and whatnot. The heads are disassembled but have not been looked at.

So far, everything has come back good..no cracks through the magnafluxing, or anything else popped up that I wasn't aware of. I'm hoping to hear back this week, so we can get the ball rolling on it getting built and hopefully in the car so I can drive it before the end of the season.

All I know for sure, it's gonna have some cam in it..lol

 

Well, almost 2 months later and I'm still waiting. I actually went in yesterday and got answers on the delays..so as frustrating as it is, it's not like the dude is just flat out kicking me to the side.

I should have a phone call coming later this morning once the sleeve is actually in (here's to hoping) as from there it'll get recleaned, and honed out to check the bore situation.

at that point, I guess I need to figure out if I want to go ahead and have it bored out even if it doesn't need it. The hot rodding side of me says yes, but the OE (and more importantly budget) side of me says to keep it as original/day 2 as possible.

 

Finally got a bit of an update...

The sleeve is finally in. It's currently going through the process of honing the other bores and checking to see if/how far the block needs bored out.

Assuming it does, I'll most likely go as little as I can (as much as I've seen how much can be sqeezed out of G blocks) That being said, what would be a good cam choice? I'm wanting something streetable but with a head turning lope..

Definitely open for even more suggestions, but I'm getting a bit more motivated on it now that it seems it's finally getting attention.

Thanks

 

Sleeving will knock the cylinders out of round on both sides of the sleeve.
Bore it.

 

I'm expecting to need some kind of boring, I'm just not going to go as far as humanly possible with it (if it needs 30 over, I'll go 30 over rather than pushing it to 40/50/60/etc)

 

**Quick update (sorta)**

After getting the same answer over the last month, I've made the decision to have the current shop finish where they're at with machining, and take it elsewhere to be built. That being said, they will build and dyno so I need to really figure out what I'm needing to do (carb/cam/etc)

ASSUMING we're looking at .030" over, what would be a good cam choice? I'm not going to be racing, but I want something that isn't a dog. I'd like as much cam as I can get while still being streetable, and not a pain when it comes to timing.

As far as carburetor, what size am I looking at? Again, streetable (most likely converted to electric choke if possible) as I know the wife will want to drive it as well.

I'll be running factory manifolds (need to get them cleaned) but am not sure on the intake as to whether or not it can be salvaged (remember, this entire engine was left out in the Ohio winter at least once). If not, it is my understanding a 455 aluminum intake will fit just right as well.

With this being a numbers matching engine, I am torn on the water pump/distributor. I have the original distributor (not sure of water pump ATM) so is it worth restoring to put in there, or am I better off restoring it at a later date and sending with the car when it sells (if it sells)

I've seen the issues with aftermarket rods, the lady I spoke with on the phone at the new shop is in charge of ordering parts. When time comes to schedule drop off/build, I do plan on coming in with as much information as I can because it sounds like they'd not done a 400 before (but have done plenty 455's, 403's, 350's, & 307's)

 

I have a 400G just like yours. I built it over ten years ago with similar goals in mind and I'm still pretty happy with it. It has:

-- Original Q-Jet, painstakingly rebuilt by an old guy who really knew what he was doing. Unfortunately he has since passed away. I've barely touched it and it's still perfect.
-- Comp Cams 262H (218/224 @0.050, 462/469, LSA 110) which in retrospect might be a bit much. It has a fairly lumpy idle but it will idle as low as 550 RPM in gear and transitions well off idle. The fenders just shake mildly, that's all.
-- Original manifolds.
-- HEI distributor. Came with, and I saw no reason to change it. After fooling around with it for years I finally took it to a shop to get a decent curve (32 degrees initial in before 3000) put in it and have been happy happy since. If I was going to get a new one, I'd probably get an MSD Ready-to-Run. If it comes with a black cap!

I would work on saving your original intake. My understanding is that there are no performance benefits to be had from the 455 aluminum one (other than weight savings) and it definitely wouldn't look like it belongs on a 400G.

Remember, these engines are long-stroke torque monsters. There's no point building them for high-RPMs -- you'll just ruin the good torque characteristics and end up scattering the rods into the pan trying to buzz it high enough to make some horsepower.

Trust me, your mileage won't vary.

 

I may take the intake in and see what they say. The ports on the intake and heads were nearly packed full of rust, but the fact it's not aluminum helps. Last I heard the heads are good, but its been so long since I'd gotten an update on the heads, I'm not 1000% certain on what he said.

Any videos? What do you mean the cam is a bit much?

Yeah, coming from screaming small blocks I've had to constantly remind myself that this is an entirely different animal..lol

 

I also rebuilt the 400G in my '69 442. I originally intended a pretty stock rebuild but we all know how that goes. The only stock component left on it is the iron block. I used a Mondello JM-18-20 cam which is pretty close to the Comp Cams spec '69442ragtop is showing. I decided to put aluminum heads on it rather than invest in the original C heads and went with a Performer intake. I don't think the Performer is too much better than the factory iron intake but, as has been noted, it weighs considerably less. I'm also running an HEI distributor. I converted the original points to Pertronix about 25 years ago and never had any problems with it but I like the HEI I'm running now just fine.
The 400G gets a bit of a bad rap from a lot of Olds guys but I've always been happy with mine. I think it's a great street performance engine and, if you respect what it's good at and what it isn't, you'll do fine. Tons of low end grunt but don't go looking for 6krpm.

 

I just meant that no 4-4-2 from the factory that wasn't a W-30 idled the way mine does. It's sort of inauthentic, but I actually like it. And it does bump the torque curve up a little as well but there's still plenty there.

Mr. Cavagnaro also makes some excellent points.

 

As far as intake, my dilemma is this...

The intake sat uncovered outside for at least 1 Ohio winter (the engine/trans did) and the amount of rust in the ports has me concerned. I could get it checked, at which point I'd use the replacement carburetor it came with (dated 72 I believe) but the easy option would be aluminum intake and aftermarket carb. I could always get the intake checked at a later date and send it with the car if we decide to sell it.

As much as I'm trying to keep things close to original, I know this shouldn't make as much difference as a bigger cam and already being bored out.

Am I trying to have my cake and eat it too?

 

Hey, Brother, for your iron intake:
Take it out in the yard and steel brush as much of the rust off as you can. Be careful, you're not trying to shine it up (at least I don't think that is what you want. Then take the manifold and place it in a shallow plastic pan and pour in Evap-o-Rust. A plastic storage bin from one of the Big Box stores works great for this. Cover the intake with (fresh) Evap-o-Rust. Let it sit overnight, and I bet you'll be impressed with the condition the next day. Evap-o-Rust uses chemical chelation to eat the rust off, and leaves behind a fantastic finish. Then clean and prep it to repaint in Bronze of your choice.

 

That is assuming there is no cracking or holes. How would I go about checking that, or is the iron generally strong enough?

I've not had any word on cracking or holes from the block or heads (aside from the 1 cylinder wall) but id think more would have pooled in/on the intake.

 

I'd be shocked if that original intake had cracks. Those things are real boat anchors. Crazy wall thickness.
The '69 Quadrajet used what they call a 'divorced' choke. That means there's a cavity cast into the manifold beside the carb. The choke spring sat in that cavity with a stamped cover over it. If you're really planning on originality, you'll need the proper part number carb and not one that may have a later electric choke conversion.
I think your idea of going with an aftermarket intake and carb makes sense. Keep the intake in case anyone wants it later but, to be honest, your car's not a W-30 or Hurst so the number of people who would care about that original intake is pretty low.

 

The Performer intake is getting really expensive unless you find a good used one. There's also the O4B (Edelbrock) some of which were flanged for your Rochester.
Shows up for sale on eBay from time to time. If you sand blast your cast iron intake it will probably look like new. Just wash it really well inside and out afterward.

 

You can keep the original Q-jet carb and manifold and convert the carb to electric choke using a conversion kit from these folks: https://www.everyday-performance.com