C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

383 or 427

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Old Dec 31, 2007 | 02:06 AM
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Default 383 or 427

Hey guys i just wanted to have everyone weight in on some options. Before i get started i'm going to put on the ol' flame suit. So i bought a 89 coupe about 3 months ago for a small amount of money and had to do a lot of work to get it back on the road, new tires, put every interior piece back in, new MC, new battery, and paint it. But now that i have it driveable I am getting ready to do some motor work. My question is, I have a brand new GMPP 350 crate motor thats never been run and have thought about possibly buying a new crank and pistons and making it a 383. But recently i've wanted to build a 427 small block, either an aluminum spring car block or a 427 stroked and bored. What do you guys think? I will probably get a LT1 intake and machine it myself to work on the motor, simply because i don't want to tinker with a SR or MR. But whats your opinion? I know there is no replacement for displacement thats why i was thinking 427.
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Old Dec 31, 2007 | 03:45 AM
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36 years ago, I was born in Memorial hospital on Romie lane in Salinas.
Still have some family in town.

Search for Caboboy in the archives here.
He is running a CA smog legal 421 cid SBC.

With the right cam and judicious tuning, I think you should go for it!

I was looking at aluminum SBC bare blocks.
New they are just about $5K!
*Edit: Found price at jegs dot com: $4,389.99
Used they are $2K and usually hurt.

Miniram = LT intake.

What transmission does your vette have?

Last edited by pablocruise; Jan 1, 2008 at 10:03 PM. Reason: added price info
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Old Dec 31, 2007 | 09:18 AM
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You can get a Dart little M block and build that big SB.
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Old Jan 1, 2008 | 11:05 AM
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For all out performance the bigger the better, go 427+. I have an aluminum sprint car block to use for my build and they are not as great as you may think for two big reasons. First, any serious sprint car engine will be set up for dry sump oiling. This means that in many cases the rear main cap will not have provisions for an oil pump. To make matters worse, they will often not have any drain back holes in the lifter valley above the cam. Second, any serious aluminum sprint block will likely be a tall deck.... That's great because now you can run a much longer rod with a ton of stroke and still have some meat up top.....but intakes don't go on a 0.250 tall deck without a lot of work. So if you can afford one, and don't mind the downside they are really good units. Like I said, I have one and wouldn't use anything else but they are not a simple substitute for a regular block. Another note, if the block is hurt that is ok in most cases. The only damage that can't be fixed is when you blow out the lifter bores. You can in fact fix a broken main but most engine builders are hesitant to do so but on the street you won't see a problem. Do you have access to a block already?
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Old Jan 1, 2008 | 11:14 AM
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your power is in the heads not displacement...invest in a good set of heads.

from there displacement only tells you where the torque curve is and not an increase in power.
A good 427 is only about 1k more expensive than a good 383. A raised cam makes it more expensive (and limited options)... raised deck hieght still more expensive (intake selection is rare)

Having said all the I am moving from a 383 to a sbc 427. This is so I can have crazy torque at 3K rpm and not rev over 6500 for fun.

Last edited by ZD1; Jan 1, 2008 at 11:18 AM.
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Old Jan 1, 2008 | 01:25 PM
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ive been slowly setting mine up for the 383 mainly for the dependability, hes right its all in the heads and you wont realize any difference in power on the street between to two, maybe a 10th of a second on the track.ive been in drag racing along time, even set the F/G record in a 63 split window. I would go for the dependability first over a 10th
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Old Jan 1, 2008 | 02:15 PM
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When I went through the same decision making process, it all boiled down to two determining factors, both of which had to be met:

1. If your car is to pass Ca smog, you cannot run too big a cam and the biggest EO# aftermarket heads are 195's. And a 427 will want some more cam or it will not run any better, if at all, than a smaller displacement engine. You also have to deal with the header issue (no EO# long tubes for a "pre-cat" car). So you have some pretty hairy breathing issues to deal with in a 427, and

2. Price out your options. I did this a couple years ago and a 427 was quite a bit more expensive than a smaller engine, due primarily to "aftermarket."

So I opted for a 406. It is simple, affordable and the engine makes good power (runs low 12's NA. With some more effort, I am sure 11's are do-able), is dead reliable, passes smog and gets good gas mileage. The 421 comment, above, is also a good one. But if you want a 427 and have the coin, go for it and don't look back. You will never be happy unless you get what you really want.

In my case, I wanted the ET slip with a DD and did not particularly care which engine got me there. A 383 can also put you in 11's-12's and the money saved on the short block is available for breathing. For me, the smaller cube engine (smaller than 427) is a better balanced package for the street. But "427" are magical numbers!

Last edited by GeosFun; Jan 1, 2008 at 02:44 PM.
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Old Jan 1, 2008 | 03:09 PM
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Hey Paul, George, how are you guys? Happy New Year to all

It doesn't sound like the OP cares about emissions, what with a miniram and all. If I wasn't concerned about emissions that's what I would've done...........either that or a modded HSR like Larry Dickey has I think Smokey Yunik said it best........"no replacement for displacement........" and all things being equal (heads, cam, etc) larger CID is gonna put more down than a smaller motor will. I think the biggest questions to answer when planning a build are:

1. Budget;
2. Smog compliance or not;
3. Budget;
4. Street driving or track;
5. And finally.......... budget

I agree with the previous statements about the heads being the single biggest contributors to the motor's power, IMHO that's the one area you can't skimp on no matter what you build. (BTW George, the new 210 Eliminators do have an EO number!) Where the hell were they when we built our motors The choice of intakes are simply gonna give your build a particular character when you match up a cam (ie: rpm or torque). I'm of the opinion that this hot rod business we do is a lot like getting into the spoon............sooner or later you want more. I'd recommend you set a realistic goal for whatever you choose, and build it to stick a couple hundred HP of nitrous on it when you get that inevitable urge to spend more and go faster. BTW, nitrous is legal in Cali !!
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Old Jan 1, 2008 | 05:42 PM
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with Cabo, inches is inches, especially if you get them from the stroke. A 4" crank is going to be as reliable as a 3.75" crank if everything's put together properly. 454" BBChevys don't have any problems with a 4" crank. (455 Pontiacs 4.21"- 455 Olds 4.25"). An aftermarket block is best; Dart is favored I think. Aluminum blocks don't cost $6000. Jegs sells Motown Aluminum blocks for $3500, cast for $2100, but I've heard some bad things about Motown. You can use a 400, or even a 350 block (409") with a 4" crank with some block fill to allow for grinding. Lunati Stroker rods and a small base cam. AFR 195 or 210s are both good to 600HP with the right parts: cam, intake, exhaust. There should be info on "Search"... Might be under 434" ( .030 over 400 w/4" crank)

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Old Jan 1, 2008 | 06:23 PM
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If anyone is interested I have a 4" Callies crank for sale (350 Mains). The crank was the $2000.00 one. It has been repaired and magged after repair by two shops including the one building my 427. It is ready to go. I was saving it for a project that I have lost interest in finishing. First $500.00 takes it. Local pick up preferred.

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Old Jan 1, 2008 | 11:28 PM
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Well an aluminum block that a full on competition effort will use like a Donovan, Rodeck, or Brodix will cost over 5000 dollars. If you want titanium main caps or weight reduction you will look at considerably more. If you guys are implying that 51 cubic inches won't make a power difference why even make the 33 cubic inch jump from the 350? Sure the heads ultimately determine how much power is made but if you have ever driven a 434 with a set of heads that flowed decent numbers you wouldn't be telling him to go 383.
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Old Jan 2, 2008 | 12:38 PM
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(BTW George, the new 210 Eliminators do have an EO number!) Where the hell were they when we built our motors

Hi Cabo! Cripes! This is the story of my life! This bodes well for the 427 decision! Darn, now I probably have to go out an get a set of 210's! I was on the fence with the 195 Elim's, since I have the old style AFR 195's. Do I hear 11's knocking?

Last edited by GeosFun; Jan 2, 2008 at 01:09 PM.
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Old Jan 2, 2008 | 02:03 PM
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Go with the iron block 427

http://www.theengineshop.com/prods_p...townBlocks.htm
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Old Jan 2, 2008 | 05:29 PM
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427! Do it!
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