Is a 427ci. worth the extra $$$ over let's say a 402-LS2?
08-27-2005, 11:06 PM
#1
Is a 427ci. worth the extra $$$ over let's say a 402-LS2? Goal: 550rwhp street motor, emmisions "friendly"(I am willing to do a cam swap for smog if this isn't possible)
This is a simple question, maybe not... Using the prices that you have in mind for these two motors from our sponsors, is a 427-LS1 really worth the extra dough over a 402-LS2?
One of these motors will go into a STREET driven 99 F-body. No plans for boost, slight chance of N2O. I can basically spend my whole budget on a 427 or save a little bit and go with the 402. I am no expert when it comes to the potential of these two options, but as has been said over and over... there is no replacement for displacement. Both will utilize an Eagle rotating assembly.
As of now... I am leaning towards the 427ci for these reasons... It is an LS1 block, meaning I use the timing set, timing cover, cam sensor, and what not out of my 346 that I could not use on the LS2 block. The 427 is pretty rare in a street driven F-body, it will definitly be something to talk about. Finally... IT'S A 427!!! When people hear that they will ooo and aww.
I would like to hear everyone's opinions, weather or not you are familiar with big bore motors. And I would definitly like some thoughts on those who actually have these two motors. Thanks a lot!
This is a simple question, maybe not... Using the prices that you have in mind for these two motors from our sponsors, is a 427-LS1 really worth the extra dough over a 402-LS2?
One of these motors will go into a STREET driven 99 F-body. No plans for boost, slight chance of N2O. I can basically spend my whole budget on a 427 or save a little bit and go with the 402. I am no expert when it comes to the potential of these two options, but as has been said over and over... there is no replacement for displacement. Both will utilize an Eagle rotating assembly.
As of now... I am leaning towards the 427ci for these reasons... It is an LS1 block, meaning I use the timing set, timing cover, cam sensor, and what not out of my 346 that I could not use on the LS2 block. The 427 is pretty rare in a street driven F-body, it will definitly be something to talk about. Finally... IT'S A 427!!! When people hear that they will ooo and aww.
I would like to hear everyone's opinions, weather or not you are familiar with big bore motors. And I would definitly like some thoughts on those who actually have these two motors. Thanks a lot!
Last edited by Ferocity02; 08-27-2005 at 11:12 PM.
08-27-2005, 11:34 PM
#3
is the budget including the top end (heads, cam, induction) as well or would the 427 cut into that part of the build up. a good set of heads and proper cam timing is where your going to make power. no sense in spending all your money on a killer bottom end only put a subpar set of heads.
the larger bore of the 427 allows the heads to breathe by unshrouding the valves. not to mention the inherent tq increase due to the extra displacement. tq in a street motor is king.
are you thinking of going with jasons block or another route? also, you could always do an iron 408, should be able to get the shortblock with eagle rotating assembly for ~3500.
if your willing to do cam swaps and can get around the visual (LT's), then i'd opt for the 402/408, plenty of 500rwhp plus packages done with AFR 225', 90/90 and full bolt ons. if however your going 100% smog legal; cam, Carb numbers, ect. then i'd opt for the 427 as it'll be the better platform to try andd achieve your goal.
the larger bore of the 427 allows the heads to breathe by unshrouding the valves. not to mention the inherent tq increase due to the extra displacement. tq in a street motor is king.
are you thinking of going with jasons block or another route? also, you could always do an iron 408, should be able to get the shortblock with eagle rotating assembly for ~3500.
if your willing to do cam swaps and can get around the visual (LT's), then i'd opt for the 402/408, plenty of 500rwhp plus packages done with AFR 225', 90/90 and full bolt ons. if however your going 100% smog legal; cam, Carb numbers, ect. then i'd opt for the 427 as it'll be the better platform to try andd achieve your goal.
08-27-2005, 11:52 PM
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I say go for the most cubes you can afford. If you really want a 427, get it, or else youll be kicking yourself for not doing so. Myself have been thinking about the differences in going with a high compression 388 soild roller, or a high compression 402 solid roller. I really want the 388, just because it has a shorter stroke and will be more rev happy, but it will cost more than the 402. My goal for both set ups is 575rw. Its still a ways off, but im doing all the reasearch now.
08-27-2005, 11:54 PM
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Depends on your buget, I would love to have gotten a 427 for my twin turbo car, but the 408 still seems to kick serious ***, spool up my twins really fast, makes great power.
Unless you just have money to burn, I would say the extra cash can be better spent someplace else.
Unless you just have money to burn, I would say the extra cash can be better spent someplace else.
08-28-2005, 12:29 AM
#7
I'm not trying to sound biast here because you are looking at buying my block, but for a N/A set-up, cubes will be king. Like JRP said, you will be able to utilze more heads because the bore unshrouds, allowing you to go up into the "top dog" heads out there. With everything being equal, the 427 will make more power and everything will bolt right up. You could also look at it as a down the road investment. Even if you don't have the "big" heads right now, you'll just have that much more power when you can get them. Every little thing you do will just make that much more over the others. Plus, It's a 427!!!! 
Last edited by Beast96Z; 08-28-2005 at 12:43 AM.
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08-28-2005, 12:43 AM
#8
This is what my current budget will allow... 427ci block and Eagle rotating assembly, assembled to short block form. Or, 402 LS2 assembled short block with Eagle rotating assembly and money left over for a decent set of heads. Basically I can get the 427 now, and finish it in the winter. The 427 block won't be left for very long, so I'd like to get it now to put in later.
jrp - By no means will the car be 100% smog legal. I just need it sniffer worthy come smog time. I'd be willing to swap cams every two years, but nonetheless I cannot get a GIANT cam because the hard hitting lope would be a sure sign of a modified motor to any cop.
jrp - By no means will the car be 100% smog legal. I just need it sniffer worthy come smog time. I'd be willing to swap cams every two years, but nonetheless I cannot get a GIANT cam because the hard hitting lope would be a sure sign of a modified motor to any cop.
08-28-2005, 06:56 AM
#14
I have a LS2 402 and love it. Agree there is no replacement for displacement, but I like the LS2 because the sleeves haven't been touched. I was worried about spending all this money on a resleeved LS1/LS2 block and maybe down the road have a problem with a sleeve. But I agree with JRP with you being out in CA then I would probably go with the 427 because you could go alittle tamer on your setup and be close to the same power output of a radical 402.
08-28-2005, 08:55 AM
#15
If 550rwhp and passing emissions is your goal, a 402 without FI or NOx won't do it. In CA, they may not pass a long tube header, so an NA 427 may be marginal. To pass emissions in CA, it has been reported here that a 224/228 114 is as far as you can go. That would not equal the big cam that you may want to keep those extra cubes well fed.
But why 427? A 427 can be 4.125 x 4.00. However, unless you have the crank and block, why not a 441? Or may shelling out the extra $$$ for the Darton 4.2 sleeve and go 457?
And with the emissions cam, this will be a torque monster, since it will be air starved had higher engine speeds. To minimize this, a big cube motor can support bigger heads. LS7 heads. The big ET Performance Heads, the AllPro Head, the big AFR head.
If you like lumpy idles, and want to change parts for emissions testing(they don't do spot checks in CA, do they?), a 402 can do it also. I imagine if you look for posts from people with a G5X3 402 or other big cam (say 236/240) and long tube headers should all be there. Rapid Motorsports had a thread about a 553rwhp 402 they built.
Note that building a 550rwhp 427, 441, 457 won't be a walk in the part still meeting emissions regs.
But why 427? A 427 can be 4.125 x 4.00. However, unless you have the crank and block, why not a 441? Or may shelling out the extra $$$ for the Darton 4.2 sleeve and go 457?
And with the emissions cam, this will be a torque monster, since it will be air starved had higher engine speeds. To minimize this, a big cube motor can support bigger heads. LS7 heads. The big ET Performance Heads, the AllPro Head, the big AFR head.
If you like lumpy idles, and want to change parts for emissions testing(they don't do spot checks in CA, do they?), a 402 can do it also. I imagine if you look for posts from people with a G5X3 402 or other big cam (say 236/240) and long tube headers should all be there. Rapid Motorsports had a thread about a 553rwhp 402 they built.
Note that building a 550rwhp 427, 441, 457 won't be a walk in the part still meeting emissions regs.
08-28-2005, 09:20 AM
#16
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Originally Posted by DavidNJ
If 550rwhp and passing emissions is your goal, a 402 without FI or NOx won't do it. In CA, they may not pass a long tube header, so an NA 427 may be marginal. To pass emissions in CA, it has been reported here that a 224/228 114 is as far as you can go. That would not equal the big cam that you may want to keep those extra cubes well fed.
But why 427? A 427 can be 4.125 x 4.00. However, unless you have the crank and block, why not a 441? Or may shelling out the extra $$$ for the Darton 4.2 sleeve and go 457?
And with the emissions cam, this will be a torque monster, since it will be air starved had higher engine speeds. To minimize this, a big cube motor can support bigger heads. LS7 heads. The big ET Performance Heads, the AllPro Head, the big AFR head.
If you like lumpy idles, and want to change parts for emissions testing(they don't do spot checks in CA, do they?), a 402 can do it also. I imagine if you look for posts from people with a G5X3 402 or other big cam (say 236/240) and long tube headers should all be there. Rapid Motorsports had a thread about a 553rwhp 402 they built.
Note that building a 550rwhp 427, 441, 457 won't be a walk in the part still meeting emissions regs.
But why 427? A 427 can be 4.125 x 4.00. However, unless you have the crank and block, why not a 441? Or may shelling out the extra $$$ for the Darton 4.2 sleeve and go 457?
And with the emissions cam, this will be a torque monster, since it will be air starved had higher engine speeds. To minimize this, a big cube motor can support bigger heads. LS7 heads. The big ET Performance Heads, the AllPro Head, the big AFR head.
If you like lumpy idles, and want to change parts for emissions testing(they don't do spot checks in CA, do they?), a 402 can do it also. I imagine if you look for posts from people with a G5X3 402 or other big cam (say 236/240) and long tube headers should all be there. Rapid Motorsports had a thread about a 553rwhp 402 they built.
Note that building a 550rwhp 427, 441, 457 won't be a walk in the part still meeting emissions regs.
08-28-2005, 10:56 AM
#17
Originally Posted by DavidNJ
To pass emissions in CA, it has been reported here that a 224/228 114 is as far as you can go. That would not equal the big cam that you may want to keep those extra cubes well fed.
