Looking for advise---409?

[Moonunit 451]

http://forus.com/moonunit/Corvette/DOA VETTEb.jpg


So, my motor went away, 114,000, bummer days. I've been working on parts to rebuild for a little bit. Got some ported polished cast heads, cast rods and the 219 cam is en-route. I've got a line on a good SR I'm trying to work out a price on. Planning forged pistons, rings, lifters, gasket kit, water pump, oil pump, and on and on it goes, deck the block and some other minor machine work. I'm in about $ 850, and figure $900 + for the SR then add all the other stuff. I'm figuring probly around $3500 or so to do it right.

So, what do I see today, but, "fresh 400 block, rods, new cast pistons, fresh crank, full set of clevite 77 bearings, oil pan, cam cover, valve covers, a set of cast iron heads done by Zimmerman's racing in Greensburg IN, a new water pump, a new balancer and flexplate. New rings, stock lifters, cam, gaskets. New oil pump, new fuel pump, and a Comp Cams 501/501 cam kit witch has a new cam, lifters, double roller timing chain, keepers, retainers, and springs. The rotating assembly has been balanced". $1350!

Under $300 to get it to me, then build it, do an exchange instead of having to have my engine out for a month to build it, then try to remember how everything goes back together. All the stuff but the intake is there, no real extra expense (splay the main, but I was going to do that anyway), and sell what I don't use, get a fair ammount of my money back.

I'll have a 400 + hp engine vs. 300+. I've talked to the guy and it's mine if I want. I believe him to be haonest and am comfortable finding a way to do the deal that will protect each of us on the financial side. I suppose there is always a chance that there may be defective parts or something, but my gut says the guy is straight up.

I'm looking for advice and comments - Quick. Thanks everyone!

 

[Mad-Mic]

i say go for it if it's a good deal and you feel confident about it!

which heads are better? the ones you already got or his?

 

[Jack]

MU:
What kind of rods ... 400-type (5.565") or 350-type (5.7")?
Others may disagree ... but IMHO you may not be so happy with anything less than 5.7" long. Also ... type of rods is crucial to determining if there's gonna be adequate rod-to-cam lobe clearance. You need 0.050"clearance cold. Even a mild hydraulic cam's lobes WILL hit OE-type 350 rods with 3.75" stroke of a 400 crank.

What is compression ratio? ... has everything to do with how much/what type cam will work for YOUR needs and what kind of gas (octane) is required.

What kind of heads ... casting number, porting, surfaced/cut ...etc.?... major effect on CR.

What kind of pistons ... dome volume ... major effect on CR.

Has block been decked? ... if so , how much ... major effect on CR.

Has block been bored ... if so, how much? ... boring an old 400 beyond +0.040" (4.165") is thin ice for anything (i.e. street) except short-run race motors.

Look before you leap.
JACK:gap

 

[Moonunit 451]

Thanks for the responses guys

Mad-Mic, As far as the P&P goes it's hard to say without seeing them, but I'm pretty sure the ones that I have are the stock, 194's (?). The ones he has are the 202-160's, so those would definately be the ones to use.

Jack, wow that's a lot of great input! I saw you were online so I dropped you a PM to see if you came up. I'll get as many of those answers as possible. I talked to this guy for quite a while, and if I recall correctly the engine was set up by his uncle who I thought he said was an engine builder, so I was taking his word that the right stuff was there, but I'll find out for sure. He said it was set up to be a 500+ hp, but told me to expect 400+ for sure. I think it went without saying that it depends on the flow in and out what you get.

I'll be planning on the 219 and the SR, probably a 58mm TB, haven't figured the exhaust yet. His comp cam 501 - (?) 501 cam set was going to be too radical for my purposes. The block has been bored .30 over.

Thanks for the great input Keep it comming folks. He did give me a lot more info on the phone, but I didn't get it all written down.

 

[Moonunit 451]

Jack, this is what I got so far, I'll have more specifics tomorrow. Some of the parts are still at his uncles who does do alot of engine building. He thinks the rods are the 350 5.7, will verify. He was a little confused about your clearance qustion "You need 0.050"clearance cold. Even a mild hydraulic cam's lobes WILL hit OE-type 350 rods with 3.75" stroke of a 400 crank.", and inquired if you were thinking 383. I told him I didn't think so based on your later comments. I also took a look at your profile and figured you knew exactly what you were talking about

Compression ratio, he thinks 10:1. I think we'll know more on that tomorrow.

Heads, he thinks GM hypro, should have casting#'s tomorrow.

Pistons, dished, he thinks C-Pro.

Not decked but I can have that done if neccesary. I wasn't really planning a 10 sec car:crazy

Thanks again for the steerage!

Oh ya, I sent him an e-mail and invited him to view this post, and chime in if he likes.

 

[Jack]

Colin:
Thanks ... but profile means nothing here ... many auto QE's don't know a rod bolt from bulkhead remover. What matters is direct & successful experience. Motor builds I know pretty well ... not so on computerized climate control ... but I look & learn.

What is "SR" you reference?
Has the motor you're considering buying been successfully run-in?

OE 305 & 350: stroke = 3.48", rod length = 5.7"
OE 400: stroke = 3.75", rod length = 5.565"
"typical" 383: stroke = 3.75", rod length is builders choice
(*GMPP/Chevy's recent HT383 crate is 3.8" stroke w/ cam-clearanced (modified) 5.7" rods & roller cam in 350-type block*)

The crank centerline-to-cam centerline dimension is same in both OE 350 & OE 400 blocks ... same in all OE GEN I small blocks ... that's why same timing chain set can fit all OE GEN I non-roller cam sbc. 400's longer stroke moves head of rod bolt closer to cam lobe ... OE 400 motor has short (IMHO undesireable) rods whose resulting rod angle widens that proximity ... regarding cam clearance that's why they work just fine in a 400. But when longer OE 350 rods are used w/ longer 400 crank ... the bolt heads are too close to the cam lobes ... even a cam with as little as .450" lift can hit top of rod bolt heads w/ OE type 350 rods and 400-type crank ... no matter if in a 350 block or 400 block. A 400 BLOCK provides no more cam clearance than a 350 block ... the 400 gets its clearance via short rods ... not the block itself. Yes, I am also referring to 383 combinations ... the cam clearance issue applies as well when using OE 350 rods. Think of it like this ... when coupled to OE 350 rods, a 400 crank's longer stroke shoves the rod bolt heads about 1/8" (0.125") closer to cam lobes than does a 350 crank. The point at which it hits (or nearly so) needs about 0.050" clearance cold. This clearance is measured with motor assembled ... put small dabs of modeling clay at cam lobes & rotate crank through 2 full revs ... then measure thinnest portion of clay ... rather tedious. An exception is an aftermarket "small base circle" cam ... its base circle is smaller that OE and resulting overall lobe height is reduced ... thus permitting higher lift. Modified 5.7" rods or aftermarket rods can also provide needed clearance. Shorter 400-type rods will work but are not so desireable IMHO.

Take a look at any sbc motor w/ oil pan off ... roll it through a couple times while looking at the cam & rod bolt heads ... you'll see how close they can get.

Not suggesting to deck block more than what's needed to level it ... but to alert you that shortened deck raises CR (compression ratio). Too much CR and you will have problems ... too little and the cam may not work ... more problems.

I suggest anyone having limited experience ... and planning/building/repairing/buying a motor should first get familiar w/ 2-3 good "how to" books.

Then there's emissions regs & laws ... their enforcement varies greatly from one locale to another ... what I can get away with around here won't fly in Kalifornia.
JACK:gap

 

[Jack]

stock injection has limits

Colin:
One more thing ... probably the most important.
I believe your car has computerized fuel injection. I don't know much about it ... but understand it won't successfully support a lot of change to cam, displacement or hotrodding unless it has been upgraded/modified accordingly. I'm a carb guy ... others here know quite a bit about FI. Maybe the "SR" means super ram induction ... dunno.
JACK:gap

 

[6shark9]

Oh, I pictured a "409!"

Now that would be cool

"Diddy-up, diddy-up, four 'O' nine"

 

[Moonunit 451]

Sure woulda been
I'll post more laterad

 

[Moonunit 451]

Fortunately, this problem did not occur in this forum, but I wanted to update those who offered help and advice to me on what happened if they are interested.

http://forums.corvetteforum.com/zerothread?id=593607

 

[Jack]

Colin:
Quite possible that motor may not ... repeat may ... not have been such a bargain for you. Good fortune may've shined on you after all.
JACK:gap