Tom400CFI

and that is what I'm working on for mine.


I only mentioned rods b/c someone above had suggested getting better rods. Being a budget build, and knowing that stock rods aren't bad, especially with better hardware, I suggested reusing your stock rods. If you found a kit, or a short block that meets your budget and happens to have better/aftermarket rods...bonus. Not necessary though. All you need to stroke is crank, pistons and a harmonic damper. The rest is PM since you have a 160k engine.

Last time I had a flywheel balanced in the manner that I described, it cost me $80. That was 20 years ago....I'd budget $150 today.

C4ProjectCar

Ahh, so all of the valvetrain components I had listed are unnecessary?
What you're saying is I just have to buy a 400 crank, new pistons, a harmonic damper, and pay to have the machinework done on my block? If so, that would make budgeting a lot easier.

Tom400CFI

Technically, yes. It would run with a new crank pistons and damper (and balanced FW), but obviously you'd also use all new bearings, seals, rings, etc. Since your block has 160k on it, it needs a bore job to have good cylinder sealing and longevity. And since you're in there, you'd install a new timing chain and and other PM items....since you have 160k. You don't NEED a cam, valve springs, or anything else to make it run and "feel fun"....the decision to do more work, either preventative (valve guides/seals/springs etc) or for performance (porting, cam, etc) is a personal decision that should be heavily "steered" by future plans/budget.

For example: If you know you'll get your FIRST intake and some cylinder heads in a year....why bother dumping any $$$ into any of your top end? It will be a hoot to drive b/c of the displacement for a while, then you can do your top end "in a year" and realize another huge gain.

But if you know that it may be 5 years until you get to it...probably a good idea to PM the heads/valve train while it's apart.

Know what I mean?

MJFuss

For 89 octane? Provided you have good quench and run aluminum heads, anything under 10:1 would probably work just fine.

If you have a new main cat it's probably just fine. Newer cats flow better than the old ones, even if they're not high-flow cats. You don't need to buy pre cats. You already have them, they are integrated into the front Y pipe and cannot be removed. You have three options for the pre cats: leave them as they are, gut them and bolt the Y pipe back on, or replace the entire front Y with a new one that has higher flow pre cats (expensive). Buying new precats and gutting them would make no sense, and you would probably not pass visual inspection without at least looking like you have precats.

When choosing a cam, you should take everything into consideration, including CR. You can get away with longer duration on an engine with more displacement too, so that's another benefit to a 400 (or 383 for that matter).

400s are not necessarily hard to find or all that expensive. They're just not as plentiful as 350 blocks. There are 3 for sale pretty cheap in my city right now.

C4ProjectCar

I gotcha. That makes sense. And I like your idea to stroke it now and wait to do the top end until later.
Real quick, what's PM mean? Preventative maintenance?
I'd like to swap in a new cam when I do this; would that entail any other replacements? I seem to recall hearing you have to replace valve springs when you replace your cam?

C4ProjectCar

Just out of curiosity (the purpose of this project is for me to learn more about engines) why can aluminum heads handle higher compression? Is it the increased cooling?

The precats are visible if you look down the side of the engine, right? If so, they're not there. There was a note in a receipt for work the previous owner had done where it was noted that there were no precats. I'm guessing someone removed them for performance.

CR means...? I read a big explanation of camshaft terminology but I just can't recall. What cam would you recommend for a 6-speed 383 running 89 octane? I'm looking for low to mid-range power, not screaming high RPMs.

I probably won't go with the 400 right now, but just so I know my options how much would a 400 block cost?

Tom400CFI

[QUOTE=C4ProjectCar;1I'd like to swap in a new cam when I do this; would that entail any other replacements? I seem to recall hearing you have to replace valve springs when you replace your cam?[/QUOTE]
Any new cam is going to have more lift than your stock cam, and more than likely, a much more aggressive "ramp rate". Meaning it will open and close the valve further and more quickly. So the stock springs will not be able to control the valve movement at higher RPM....you'd need to change valve springs. If you have springs off...might as well change the seals. Don't look too close at the guides though, if you're not going to do them!

C4ProjectCar

I'm trying to estimate cost. I have down about $150 for new valve springs and practically nothing for new valve stem seals. Does this sound right?
And about what should I expect to pay for some decent valve guides?
EDIT: Googled it. Looks like 100 bucks or so?

Tom400CFI

Found several w/a quick search ranging in price from $80 (bare block) to $1250 (full short block)

May not be a 400?

Doesn't know how to spell...

Full Short block...

C4ProjectCar

Your link titles are hilarious!

What would I have to buy to do the 400 that I wouldn't to do the 383?

EDIT: Also, blocks are different for roller cams than for flat tappet cams, right? How do you tell the difference on a Craigslist post etc?

Tom400CFI

Glad you liked them. I mean, if you're going to place and add, could you take 10 seconds and check the spelling? Yikes.


1. Maybe a flywheel, and maybe roller lifters. No 400 ever had a roller cam, so to get a roller cam you'd have to buy "retrofit roller lifters" OR retrofit/DIY your old lifters and "spider plate" (retainer) to make it a roller cam engine.
Also, no 400 ever had a one piece rear main seal, so you'd have to either
A. redrill and bore your stock flywheel flange for the 2 piece crank, then balance appropriately, or
B. Buy a "single mass" flywheel for that application

2. If you can see a pic of the rear of the engine, you can tell if it's a 2 piece rear main seal engine and that would mean it came (originally) with a flat tappet cam. Look at the crank flange:


Here is the later 1 piece rear main seal. Note the lack of a "counterweight", and the crank flange doesn't protrude (much) beyond the seal:

^This could have been flat tappet OR roller, and the split was probably about 50/50. so hard to tell by looking at pics. Best just to ask the seller.

Otherwise, differences between a 350 block and a 400 block are limited to the aforementioned steam holes required in the heads, and the bore size.

C4ProjectCar

My thoughts exactly concerning proofreading. It's one thing for a short block, but it's worse when it's for a $5k+ Corvette.

The 400 seems like more than I want to bite off right now, but I'll keep it in mind.

Wait - you said both pictures are 1 piece. They look different.

Tom400CFI

Guess I need to take my own advice and check! I just edited above, but the first pic was an older 2 piece engine (like all 400's) and the second pic is a later 1 piece like what you currently have in your car now.

C4ProjectCar

Okay, thanks. Would 2 piece/1 piece be related to internal/external balancing?
I'm trying to nail down my plans for my stroker. What cam would you suggest?
I spotted this one on Craigslist for cheap:
http://stockton.craigslist.org/pts/4570636766.html
It's a CC XR270HR

MJFuss

If I were you, I'd just shop around locally for a while. Maybe you'll find a really good deal on a 383, maybe a 400, who knows maybe even a 377.

On craigslist you'll often see folks selling expensive setups that just haven't been assembled yet.

Once you have a short block (or the parts to build one), you can start to think about what cam you should use. Not every block is set up to use a roller cam with your oem roller lifters, and going aftermarket roller is expensive.

The best policy for cams is to use the lifters and springs specifically recommended for the that particular cam by the manufacturer. If you call one of these places they can help to guide your cam selection based on the engine displacement, heads, intake, intended use, and a host of other things.

Most of all: read Vizard's book (or a similar one). It will answer all of these questions plus hundreds of others you'll never think to ask. When doing your own thing with an engine you need to know lots of stuff! There's also a SBC parts interchange book that can be very helpful if you're pulling together parts on a tight budget.

Whatever happens, don't get carried away with cost, and make sure you know all of the costs for a build up front, as much as possible. A brand new Blue Print 450 hp/tq 383 crate engine, complete (even with stuff you don't need and could sell, like the intake manifold and HEI distributor) and ready to run with a 50k mile warranty can be purchased from Speedway for $3500. You might even find you can buy one like it locally, with very few miles, for half that price. Lot's of people spend big bucks on engines and then change their minds, or get in over their heads with the car project. Their stuff sells at a steep discount. You don't want to be the guy who makes that mistake, you want to be the guy who steps in and takes advantage of it.

Tom400CFI

If you do pursue the 400 here are your two roller lifter options;
1. is to buy the "retrofit lifter kit". Lifters look like this, using a "link bar" to keep them aligned.


2. DIY using junk yard parts or the parts from your current engine. LIKE THIS GUY DID It ends up looking and working like a factory set up b/c it's all factory parts, using "dog bones" to align the lifters, and a "spider plate" to hold them down. This is what your car has in it now....

Tom400CFI

C4ProjectCar

Okay, thanks.

I was planning to stick with a roller block, because I heard they performed better. Is this not the case?

Huh, I didn't know about matching rollers and springs to cams. Is that for both types of cams or just flat tappet? I'd heard that for roller cams the LS7 lifters are nearly always the best way to go.

I plan on getting his book and reading it, I just haven't gotten it quite yet.

That cheap for a crate engine? Wow.

C4ProjectCar

Thanks for the info on retrofitting a roller cam, Tom.

Tom400CFI

You bet! Roller blocks only "perform better" b/c they have roller CAMS inside. There is nothing different/special/better about the block itself and how it works or makes power. Only advantage is the 1 pc rear seal, and the fact that it's already configured to accept a roller cam. Functionally they're the same.


You can use any hydraulic roller lifter on any hydraulic roller cam. And that is what you'd be in the market for. You are correct, flat tappet cams, once run the lifter needs to stay w/the same cam, and even the same lobe.

I'm an hour ahead of you....gotta go to bed.