View Full Version : 427 vs 454


70RS/SS396
08-07-2006, 02:33:23 PM
Hello

I just want to hear your opinion when it comes to street power, 427ci vs 454ci.

Some people say that the 427ci is more aggresive, and easier to get more power of. And its tolerate more RPM because the shorter stroke.

/ Kristoffer

theflash
08-07-2006, 04:11:54 PM
No replacement for displacement. I was facing the same notion when I wanted a BB. I chose the 454, and I tell you, I couldn't imagine something reving faster than this motor, a lot more than my old sbc.

80'427
08-07-2006, 05:56:27 PM
I chose 427 cause of the cheap forged crank but now I would go 4.25 and get a 496. I would go 454 at least unless you have all the 427 pieces.

Brian Callahan
08-07-2006, 10:35:50 PM
Street? There is no rule against displacement, so go as big as you can. For a given maximum power, it will be nicer to drive and more tractable at part throttle. It will also idle better.

muscl car
08-08-2006, 12:11:38 AM
the 427 has alot of racing heritage from the earlier days , a all aluminum ZL1 is actually based off of the 427 .now for me a 427 has a a certain statement or feel because of it's vast racing history

70RS/SS396
08-08-2006, 06:33:09 AM
I chose 427 cause of the cheap forged crank but now I would go 4.25 and get a 496. I would go 454 at least unless you have all the 427 pieces.

I just thought building a 427 of my 402 in the future, because I got the 396/402/427 crank now, onley thing I need is a 427 or a 454 block.

lluciano77
08-08-2006, 08:19:31 AM
Most old timers will tell you tell run the 427. They would also tell me to run a pop-up piston 327 instead of my 400.Times have changed. Displacement, compression, and aftermarket heads are the way to go.

The more displacement you have, the less RPMs you need to spin. I always hear people talking about high revs. F' that. Why not make the same or more power in an RPM range that doesn't break parts? Why not make the same power or more and have a better idle quality?

Even better, there are stroker kits for the 454 that are super cheap. I almost went big block, but I wanted to try to keep the handling characteristics of my Camaro, and make it fast.

Here is the kit I would use if I went big block:
http://cgi.ebay.com/ebaymotors/NEW-BB-CHEVY-540-ci-BBC-EAGLE-CRANK-RODS-SRP-PISTONS_W0QQcmdZViewItemQQcategoryZ33620QQihZ019QQitemZ7910440394

70RS/SS396
08-08-2006, 08:51:16 AM
Yeah. I friend of mine bought a 540 ci motor to his chevelle 68. 700+ hp and VERY good idle, and its streetdriven.
But its not cheap to buy such of things here in sweden, and if I order direct from usa, theres expensinve shippingcharge and 25% value-added tax.

Damon
08-08-2006, 11:27:09 AM
454 is basically a "stroker 427." It's got ~1/4" more stroke but shares the same 4-1/4" bore. I'll take the bigger cubes any day of the week.

Also, if you're considering aftermarket heads or the larger chamber factory heads (open chambers) you'll have a LOT easier time getting reasonable compression without using rediculous domes if you go with a larger cube motor. Almost all aftermarket heads are based off the factory "open chamber" design, and for good reason- they unshroud the valves and flow much better than earlier "closed chamber" heads. Unfortunately, that also means the combustion chambers are HUGE. Typically ~120cc. Even on a 454 it takes a BIG dome to get compression out of the toilet. On a smaller 427 you'd need even larger domes than that.

Think it through before you decide.

FYI- what makes an engine feel "free revving" has little to do with the bore/stroke ratio. It has everything to do with how well you match your heads and cam (and the rest of the combo).

70RS/SS396
08-08-2006, 11:52:21 AM
Yeah, but I just thought I should save some money and build a 427 of my 402 suff like, crank, flexplate, harmonic balanser etc. If I should build a 454 I need another crank, felxplate, harmonic balanser etc. I cant use anything I allready got.

Lets pretend we have one 427 and one 454. Both motors with exact same stuff.
FOR EXAMPLE
Cylinger heads: Brodix Race-Rite Oval port.
Intake Manifold: Edelbrock Air-gap Performer RPM
Camshaft: Comp Cams # 11-250-3 - 574"/578" lift 284/296 dur.
Carb: Holley 850 cfm

What can the difference in hp and torque be?

onovakind67
08-08-2006, 12:15:08 PM
A rough guess...

RPMиииииииииии2000ииии2500ииии3000ииии3500ииии4000ииии4500ииии5000ииии5500ииии6000ииии6500
427:
Brake_Tqииииии291иииии418иииии449иииии458иииии480иииии487иииии476иииии449иииии395иииии268
Brake_HPииииии111иииии199иииии256иииии305иииии366иииии417иииии453иииии470иииии451иииии331
454:
Brake_Tqииииии326иииии455иииии480иииии493иииии513иииии514иииии496иииии458иииии373иииии242
Brake_HPииииии124иииии217иииии274иииии328иииии391иииии441иииии472иииии479иииии426иииии299

At anything below about 5600 rpm the 454 has a significant advantage. Most guys I know spend more time below 5600 rpm than above it.

Damon
08-08-2006, 10:17:20 PM
I guess I missed something here.... how exactly are you planning to make a 402 (with a 4.125" bore) into a 427 (with a 4.25" bore)? That's a heluva overbore job.... or you're talking about dropping a 454 crank into a 402 (which would also give you 427ci), but would require the use of a 454 balancer/flexplate combo anyway plus a set of pistons that I don't think anyone offers off-the-shelf.

I suppose you could get a bare 454 block and drop your 402 roatating parts into it, except you'd need different pistons and definitely a re-balance job. That would also get you to 427ci.

What exactly are you trying to do here?

70RS/SS396
08-09-2006, 03:58:46 AM
Take a 454 block and drop my roatating parts into it. Yes, need new pistons.

402z28
08-10-2006, 11:33:21 PM
it's easier than you think. My previous motor was a frankenstien 427. I dropped the the 402 rotating assembly into a 454 block. The hardest part of this buildup is finding pistons. And don't forget to get your rotating assembly rebalanced for that block.

I have almost everything to build another in the same form. Just need the pistons and rings.

70RS/SS396
08-11-2006, 12:49:58 PM
What do I need to reach 580-600 hp in i 427?

IF I build a 427, Im planning to MAYBE get the Brodix Race Rite Oval Aluminium cylinder heads.
But what camshaft ect. do I need to reach 580-600 hp in a friendly streetdriven 427?

theflash
08-11-2006, 01:40:33 PM
What do I need to reach 580-600 hp in i 427?


Put a blower on it.

This post has some good insight on the topic.

http://www.nastyz28.com/forum/showthread.php?t=59815

70RS/SS396
08-11-2006, 01:57:02 PM
No, no blower :)

MyBoTy
08-11-2006, 05:01:16 PM
580 - 600 hp in a 427 without a blower or hairdryer is gonna be pretty rough on the street. At 1.4 hp per cubic inch, that's big hydraulic roller (not very 427 high rev friendly) or a moderate solid roller. I don't know that racerites are gonna flow enough air to take you to the rpm level you'll need to make that hp number. Why not build a 496 out of the same block? A very wise engine builder told me time and time again when I kept bringing up the 427: "Build it as big and powerful as you can or you'll always wish you had". Once you get a pretty good grip on 600hp, you'll want 700 and that'll be a lot easier to get to with a 496 than a 427. Cubes are where it's at, man. Build it internally balanced and it'll be your word against theirs that it's a 427 - nobody can tell without measuring the stroke that it's a 496!

70RS/SS396
08-11-2006, 05:18:33 PM
580 - 600 hp in a 427 without a blower or hairdryer is gonna be pretty rough on the street. At 1.4 hp per cubic inch, that's big hydraulic roller (not very 427 high rev friendly) or a moderate solid roller. I don't know that racerites are gonna flow enough air to take you to the rpm level you'll need to make that hp number. Why not build a 496 out of the same block? A very wise engine builder told me time and time again when I kept bringing up the 427: "Build it as big and powerful as you can or you'll always wish you had". Once you get a pretty good grip on 600hp, you'll want 700 and that'll be a lot easier to get to with a 496 than a 427. Cubes are where it's at, man. Build it internally balanced and it'll be your word against theirs that it's a 427 - nobody can tell without measuring the stroke that it's a 496!

Yes, a 496 would have been the best choice. But its to expensive for me right now. And here in sweden its VERY expensive. The reason that I want to build a 427 is that I already have the 402 crank and rods.

80'427
08-11-2006, 06:31:07 PM
If you have the crank and rods build a 427. A 454 may run better but my oval port solid cam 427 was a slouch and now with a solid roller it may really scream. Plus is you want to have a good reason, because of the lowend torque loss it may help to hook it.

70RS/SS396
08-12-2006, 08:54:35 AM
Yes, a camshaft like this should be nice i think.

http://store.summitracing.com/partdetail.asp?part=CCA%2D11%2D771%2D8&N=700+115&autoview=sku