sowaidi

iTrader: (5)

I would like your guys' suggestions for a motor build. I am in the process of buying a built motor for my RCSB 04 truck and I would like to get over 510rwhp and still be street friendly. Would a LS7 427 with high flow heads (PRC247cc or ported LS7 heads) and a medium cam be enough or would I have to step bigger for the LSX454? And If I do step to the iron LSX454 then I'd probably want more power like 530rwhp.
I am keeping my truck as a sleeper and driving it almost daily but I do not want to have issues with the 4.125 stroke so I was more interested in a 427. Its really hot where I live now and I use the AC whenever I'm driving.
The truck has a T56 and 4.10s so I would think that would help with drivetrain loss

All input is appreciated.
Thank You

LS6427

iTrader: (2)

My builder did an iron 422ci for a friend that made 535RWHP with ported LS6 heads and ported LS6 intake.. 510 RWHP is sooooo old news.

Yes, you can easily make 650 FWHP and have it be very street friendly. Look at my 427ci, made almost 500 RWHP back in 2002.

Build a budget engine using an LQ9, 4.1" stroke x 4.030" bore = 418ci. Or, 4" stroke x 4.030" bore = 408ci. Ported L92 heads and a L76 intake with a cam in the 230's. It will make 525 RWHP or around there. My builder builds them all the time.......stock crank, forged rods and pistons. Cheap.

If you want to go 427ci you might want to think about a resleeved aluminum block, but thats more cash. With the iron 418ci you can also hit it all day long with a 150-200 shot......then you'll be making ~725 RWHP.

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sowaidi

iTrader: (5)

You know its a truck so the drivetrain loss is more than your car. So you mean I would easily be able to even make over 530 daily driven rwhp on my truxk with the 427 with 247cc heads and a mild cam and I wouldn't actually have to step up to the iron block?

Thanks
Appreciate all comments and replies

WKMCD

iTrader: (2)

My car runs an extremely mild 427. 4.125 bore x 4.00 stroke. Darton Sleeved LS2 block. I drive it in DC's rush hour traffic and take it on long trips. It's a great little grocery getter. It's got plenty of grunt. I can cruise down to 600RPM and pull away cleanly if I'm too lazy to shift.

Bottom line is the 403 - top line is the 427.



Build thread:

https://ls1tech.com/forums/generatio...b-c-d-e-f.html

LS6427

iTrader: (2)

No, you do not need an iron block. But if you just want a 408ci - 418ci you can get one for $400.00

But if you want to go 427ci or larger than you really need to get a resleeved aluminum block and then the price jumps to something like $2400 for a complete, ready to assemble, block. The sleeves allow longer strokes and larger bores and still have plenty of strength after machining is done.
The LQ9 iron blocks were put into other types of vehicles like vans and trucks, there's a bunch around in junk yards and ebay. There was one on there yesterday for $400.00

The iron block would get a light hone to 4.030 bore and then you put a 4" forged crank = 408ci Or a 4.1" stroke crank = 418ci

Forged rotating assemblies (crank, rods, pistons) are $1,795
Machining = approximately $300

Total with rings and gaskets and assembly = approximately $3,000 for the complete forged short block. 700-800 RWHP capable.

.......IT ALL DEPENDS ON YOUR BUDGET.......so how much cash do you have to spend?

And YES....with the 408 -416 you can make a good 525-530 RWHP with a rather nice smooth cam. And of course if you go aluminum resleeved block you can go up to 650 RWHP with the proper budget.

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sowaidi

iTrader: (5)

First of all, All input is very appreciated and I do not want to make a decision then regret it, this is why I am open to you guys' comments and suggestions.
I'd prefer to get a complete built motor. My budget is $11K for a complete long block. No power adders or nitrous. Keeping a low profile as much as I can with a medium to medium high cam. Would actually prefer a motor built with a 4.00 stroke.

jmilz28

iTrader: (13)

If you are truly going to drive it daily, get the mildest, lowest lift cam to get you there. If you really put miles on it, you don't want to be changing springs every year. With your budget, I'd find a pull out LS7, have Advanced Induction work the factory heads and match up a 102/102 combo and you'll be right there in your power goal range even with the factory cam. Make sure you get 1 7/8" or 2" primaries on the headers. This will give you your power and OEM valvetrain life. You could always put in a MILD cam and not give up much. The only other way I would consider is any 416+ short block (iron or Al), call Tony Mamo and have him work you up a heads/cam/intake combo. This may push you out of your budget. The truth is, when you step on the gas, you will want more cam. When you're changing springs a year or two later or other parts breakage, you'll wish you'd gone smaller. Gotta be realistic about your usage and tolerance and go from there. Given your goals, I'd limit my choices to AI, Mamo, or PatG and let whomever you choose handle the entire valvetrain and top end.

LS6427

iTrader: (2)

11K will be enough to EASILY build yourself a 427ci long block. It will idle very nicely and you'll go way over your 510 RWHP goal. Probably closer to 600 RWHP.

Look at my 427ci below. I put 173,000 miles on it....it failed one month ago. Never once had a repair on the bottom end. I had the heads fully rebuilt after 5 years for $600.00. Then drove it another 5+ years till a rod broke last month. Built right, take care of it properly, you'll have the engine running strong for 10+ years...easy.

Do a resleeved LS2 block about $2400, basic forged rotating assembly for $2,100 (TSP part#25-TSP427LS7RA would do fine for N/A only application), ported L92 heads and ported L76 intake $2,000. Gaskets, oil pump, cam, lifters, pushrods, etc......

You'll come in under that 11K for sure. You should have a good 550-575 RWHP through an M6. And a motor you could spray with nitrous if you want to, maybe a 150 shot.

.

ss454327

iTrader: (10)

This is what I would do...

TSP 421 iron short block-$3850 (shipped to your door)
TSP custom 243/246 LSL/LXL cam-$389
TSP chrome moly pushrods-$129
TEA TFS 235-$2450
FAST 102/102-$1800 (intake/TB/rails/injectors)

I'd bet you could get a package deal for all this plus any gaskets misc parts needed from TSP. You could probably get them to build this in a long block ready to drop in for less than your budget...

sowaidi

iTrader: (5)

A lot of guys on the forums state its very hard to get 550rwhp with a 427 and still be a mild driver but instead it would be a street beast which I would love but could NOT have at my area because of strict cops and stupid emissions whom would fail you for having a very loud vehicle. That's why I plan to use a muffler and a resonator with a cutout.

This motor is the first I though about but I am worried about a 4.00+ stroke and wouldn't mind paying extra for reliability.

Would I get to my power goals with the TSP427+PRC LS7 heads+230's/240's cam+full exhaust+102/102+right size injectors?
I am assuming 23% drivetrain loss on the truck due to a past dyno I did on an old setup with the T56 so I am basically shooting for exactly 663fwhp to equate to 510rwhp on the truck with the M6.

02sslayer

iTrader: (4)

i am in a simular boat as you for an engine build. you can get an LSX440 with a 4.00 stroke, or you can get an ERL block that will support the 4.125 stroke which is what i think im gonna go with. but if your only wanting 530rwhp then the 427 will be plenty of CI

sowaidi

iTrader: (5)

TSP builds their LSX blocks with 4.125 stroke and 4.125 bores. Since they're closed today, Do you think they would build the them with a 4.185 bore if I choose the custom piston set and a 4.00 stroke?

Thanks a lot

02sslayer

iTrader: (4)

ya they should, i dont think that would be a problem. the LSX440 uses 4.185x4.00

sowaidi

iTrader: (5)

Which heads would work better with the setup? 247cc, LS7 265cc or LS7 285cc?
and which cam below would work better with the truck setup?
235/239 .621/.624 114 LSA+2
239/247 .624/.624 114 LSA+3
235/243 .621/.624 114 LSA+3
243/251 .624/.624 114 LSA+3

All input is appreciated.
Thanks

intenseblue

iTrader: (1)

I'd do the first set of heads and the third cam

sowaidi

iTrader: (5)

Thanks for your suggestion. I am not well educated in the concept. Why did you choose the 247cc and why not the LS7 heads with their better flow?

Thanks again everyone for your help.
It is very much appreciated

LS6427

iTrader: (2)

Not hard to have a decent idling engine at 550 RWHP with 427ci. Even easier going with a 4.125 x 4.125 = 441ci

My 427ci idled almost like stock idle. Zero lope. If I upgraded my cheesy LS1 heads and intake to ported LS7 heads and ported LS7 intake and TB to match.....small cam upgrade.....it would get close to 600 RWHP. I would go from 300cfm flowing heads to 400cfm flowing heads. Many builders have told me you can get 1 - 1.5 HP per cfm increase in head flow with a matching cam upgrade. Thats a 100 HP increase.

Build the biggest cubic inch engine you can that your budget will allow.......the extra cubes will make more power and allow for a better idle.


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sowaidi

iTrader: (5)

Thanks everyone for your help in this post and discussion. So what would you do if you were in my shoes? What would you think is the most powerful build for a STREET-FRIENDLY 427?
I am willing to spend extra so I won't regeret anything laterwise. I would love more than 510rwhp even if I break the bank but of course would love low and midrange power.

All input greatfully appreciated...

02sslayer

iTrader: (4)

along with big CI you need a topend that is equally as good and one that is well put together. dont try to peice together a head and cam package your self, have a professional do it for you like tony mamo at AFR. dont buy shelf cam or snything like that, infact i dont think there are alot of shelf cams for big CI

02sslayer

iTrader: (4)

also if you want 510 at the wheels a 427 would get you there and then some.