427cu or 540cu......
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
427cu or 540cu......
I have be kitting up to replace the small block in my 69 with 427. I believe the car to be a factory 435hp car. I have early alloy heads and few other parts sorted.
A good Mate is a big block nut, he thinks I am mad to spend all this money on a 427........ as visually will be hard to tell the difference.
Now a reasonably priced 540cu has become available, with would cost me about the same as the 427 to build, but with new heads RHS ( I read that the old alloy GM castings are prone to cracking )
I like the idea of 600hp plus on pump gas, new generation heads ect, but am scared about busting up the drivetrain, gas economy ( if you can use 540 and gas economy in the same sentence).
The other part of me is saying 427 on BFG's will be plenty of hp, gas economy will be some what better, and the car in an origional configuration......
Thoughts
A good Mate is a big block nut, he thinks I am mad to spend all this money on a 427........ as visually will be hard to tell the difference.
Now a reasonably priced 540cu has become available, with would cost me about the same as the 427 to build, but with new heads RHS ( I read that the old alloy GM castings are prone to cracking )
I like the idea of 600hp plus on pump gas, new generation heads ect, but am scared about busting up the drivetrain, gas economy ( if you can use 540 and gas economy in the same sentence).
The other part of me is saying 427 on BFG's will be plenty of hp, gas economy will be some what better, and the car in an origional configuration......
Thoughts
Race Director
Joined: Jan 2000
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From: Corsicana, Tx
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No brainer..go for the 540. I love 427's....but your friend has it right.
Tell us about the 540 combo.
JIM
Tell us about the 540 combo.
JIM
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
mate has some RHS 360cc new alloy heads, have not worked out the cam yet, but 540 would need quite a bit of cam, may even just go hyd flat tapped...not sure, always had solid flat or solid roller in the past.
Would like a bit more compression, 10-10:5 think with the pistons and the 119cc heads about 9:5 according to the JE piston calculator
Race Director
Joined: Jan 2000
Posts: 13,018
Likes: 2,262
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
It's tough to get compression with the flat tops. 10.5 is a good range to be in. I started there...moved to 11.06 and now have it at 11.4. No problems on pump gas.
Do you have heads already? Those are pretty big for a low compression motor with a mild cam like you're describing.
JIM
Do you have heads already? Those are pretty big for a low compression motor with a mild cam like you're describing.
JIM
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
[QUOTE=427Hotrod;1575652469]It's tough to get compression with the flat tops. 10.5 is a good range to be in. I started there...moved to 11.06 and now have it at 11.4. No problems on pump gas.
Do you have heads already? Those are pretty big for a low compression motor with a mild cam like you're describing.
Yeah they are big, no I have not bought them yet ( he has several sets), can get smaller ones as well, perhaps a good excuse to up the cam and comp, suppose can mill the heads and deck the block, do you know how far you can go with this path with flat top pistons?
Do you have heads already? Those are pretty big for a low compression motor with a mild cam like you're describing.
Yeah they are big, no I have not bought them yet ( he has several sets), can get smaller ones as well, perhaps a good excuse to up the cam and comp, suppose can mill the heads and deck the block, do you know how far you can go with this path with flat top pistons?
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
The original Pro Topline 320cc head is actually a better head than the 360 - decks are thicker and incoming air encounters a straighter shot at the back of the valve, the short turn is straightened considerably. Plus, they respond well to porting...
Le Mans Master
Joined: Dec 2006
Posts: 5,557
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From: Oquirrh Mountains
St. Jude Donor '09
"reasonably priced" 540 is a bit of an oxymoron. 
You'll have to decide which plug wire to leave off for 600 hp.
That being said, I just built one for mine very similiar to what you're thinking. Search my user name if interested but Jim's (427 Hotrod) 'da man' when it comes to these BIG, big blocks.
360 heads are too big for the combo you're suggesting. Use 320's as discusses earlier.
Why the flat top pistons? Do you have those already?
You'll have to decide which plug wire to leave off for 600 hp.That being said, I just built one for mine very similiar to what you're thinking. Search my user name if interested but Jim's (427 Hotrod) 'da man' when it comes to these BIG, big blocks.
360 heads are too big for the combo you're suggesting. Use 320's as discusses earlier.
Why the flat top pistons? Do you have those already?
Last edited by Ben Lurkin; Oct 18, 2010 at 11:49 AM.
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Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
"reasonably priced" 540 is a bit of an oxymoron. You'll have to decide which plug wire to leave off for 600 hp.
That being said, I just built one for mine very similiar to what you're thinking. Search my user name if interested but Jim's (427 Hotrod) 'da man' when it comes to these BIG, big blocks.
360 heads are too big for the combo you're suggesting. Use 320's as discusses earlier.
Why the flat top pistons? Do you have those already?
You'll have to decide which plug wire to leave off for 600 hp.That being said, I just built one for mine very similiar to what you're thinking. Search my user name if interested but Jim's (427 Hotrod) 'da man' when it comes to these BIG, big blocks.
360 heads are too big for the combo you're suggesting. Use 320's as discusses earlier.
Why the flat top pistons? Do you have those already?
To be honest I think if I go down the big big block route I would like to run as much compression as possible, thus domed pistons. Yes Jims seems to be very knowlegeable on these engines
Thanks
Racer
Joined: Oct 2006
Posts: 435
Likes: 18
From: Florida
I will go against the grain , and say that you should definitely cam it, and run the 360cc heads, I don't know where these guys get there info from, but out of the box RHS 360 will flow 380cfm @ .600 & 400cfm @ .700 lift. Its not a 454, why build it like one? Mill the heads for desired compression.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Is your goal to build a particular vehicle or have raging power? If you have no need for the raw torque of a 540, don't go there. You will definitely need to upgrade the drivetrain in order to make use of that power without tearing up the drivetrain. If you don't want to go to that much trouble, just don't take the first step. You can do a number of things to a 427 to make it more "friendly" or "wilder". But, if your vision is not one of burning the wheels off the car, stay with the 427 (or 454) approach. If you stay with the smaller engine, you will not likely be the 'puny' kid on the block.
Team Owner
Joined: Feb 1999
Posts: 34,454
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From: Republic of Texas
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Is your goal to build a particular vehicle or have raging power? If you have no need for the raw torque of a 540, don't go there. You will definitely need to upgrade the drivetrain in order to make use of that power without tearing up the drivetrain. If you don't want to go to that much trouble, just don't take the first step. You can do a number of things to a 427 to make it more "friendly" or "wilder". But, if your vision is not one of burning the wheels off the car, stay with the 427 (or 454) approach. If you stay with the smaller engine, you will not likely be the 'puny' kid on the block.
I am worried that if i build a pump gas freindly 427 it will take away its character and the scary power......BUT it an only planning on running BFG's tires so I guess that will be the limiting factor with all this.
Maybe the answer lies some where between the 427 and the 540, I would like to keep the mechanical fuel pump too. If I dont have to pay for a date cast block and use a later 4 bolt 454 block will cut the cost heaps..... and a 502 block bored 4.5 scares me a bit for cooling ...
Drifting
Joined: Oct 2005
Posts: 1,528
Likes: 148
From: East London/SW Essex UK
I went to 489 ci in using a stroker crank in a 'seasoned', re-built 454 4 bolt block. Brodix Race Rite oval port heads, hydraulic cam. With 500+ genuine hp and 550+ ft/lb torque it has similar economy to stock L36, still uses stock drivetrain, 3.08 rear end and M21 is great in traffic (with DeWitt rad). With these heads (stock height port location) it can still use commercially available headers although needed L88 type hood for carb/air cleaner clearance.
Team Owner
Joined: Nov 2004
Posts: 20,715
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From: Sorrento Italy
I've been thinking to replace my fearless 575hp 406ci SB engine with an upgraded one, can't make up my mind...
Here are two 750 hp option from ''American Speed'' engine builder (I have one of their 575hp 406 SB since a few years now and never had a prob...I reckon they're top guys hands down...), one is a supercharged 406 SB, the other is an ''atmospheric'' 540 BB...
1) 406 CID Brutus 750 Supercharged engine
Dart engine block, Comp Cams roller hyd. roller cam, 210 CNC comp. ported aluminum cylinder heads, ASE 4340 steel crankshaft, ASE 4340 6" steel rods, JE 8.0 comp. pistons, Mallory dist, alum. water pump, Pro Systems blower carbs...
750 hp $16,695.00
2) 540 CID Brutus 750 engine
AFR aluminum cyl. heads, Dart iron block, Comp roller cam, ASE 4340 steel crank and rods, Canton oil pan, JE 10.5 forged pistons, Pro Systems 950 carb, Mallory dist...
750 hp $14,995.00
3) Same as above but with alu Brodix block....17.895 usd.
All above price are for long blk engines, you need to add another 2.500 usd on top of that to make them full and ready to go...
Which one would you choose for my application?
My C3 has been lightened down to 2.750lbs so lightness is one of my top of the line priorities.
(...and sorry for the small hijack...
)
Here are two 750 hp option from ''American Speed'' engine builder (I have one of their 575hp 406 SB since a few years now and never had a prob...I reckon they're top guys hands down...), one is a supercharged 406 SB, the other is an ''atmospheric'' 540 BB...
1) 406 CID Brutus 750 Supercharged engine
Dart engine block, Comp Cams roller hyd. roller cam, 210 CNC comp. ported aluminum cylinder heads, ASE 4340 steel crankshaft, ASE 4340 6" steel rods, JE 8.0 comp. pistons, Mallory dist, alum. water pump, Pro Systems blower carbs...
750 hp $16,695.00
2) 540 CID Brutus 750 engine
AFR aluminum cyl. heads, Dart iron block, Comp roller cam, ASE 4340 steel crank and rods, Canton oil pan, JE 10.5 forged pistons, Pro Systems 950 carb, Mallory dist...
750 hp $14,995.00
3) Same as above but with alu Brodix block....17.895 usd.
All above price are for long blk engines, you need to add another 2.500 usd on top of that to make them full and ready to go...
Which one would you choose for my application?
My C3 has been lightened down to 2.750lbs so lightness is one of my top of the line priorities.
(...and sorry for the small hijack...
)