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Can you get 500 N/A HP out of an LT1?


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My buddy at work is going to be replacing the BBC 427 that is in his 84' Cutlass with a SBC. Now he really wants to go with EFI to save a little bit on fuel economy and for reliabilty reasons. Now he also wants close to 500HP. I know that once you get over the 1HP:1cubic inch ratio it gets less reliable but is that the same for an EFI motor?(it should atleast be better than a carbed engine right?)

 

So what would it take as far as a heads and cam combo to get this to 500 N/A HP. He's not sure if he wants to stroke it or not...

 

So with a 355cid LT1 whats it going to take??? I know it will need atlest 42# injectors, probably heads that flow in the 280-300cfm range(that's enough to support 500HP right?), long tube headers, and some better rods and pistons than stock. I think he will have compression around 11:1 or so depending on the cam.

 

Grumpy???

 

Guy

 

 

Oh and yes I know the LS1 is a great engine but it is to much $$$, so please dont tell me that is the way to go because its not happening :D Although he wishes it was!

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Look at what the people on Camaroz28.com are running. If you look around, there's also a group purchase on cam packages going on until the end of the month. If you're talking about flywheel hp, It should be possible to get close to your goal without pulling the engine. There are plenty of LT1's with dyno proven 400 rwhp on stock bottom ends. There are a few here: http://www.advancedinduction.com/

 

This guy put down 471 rwhp through a 401 ci LT1 all motor. He also ran 10.80 @ 130 in his Camaro.

http://www.fastblackcar.com/camaro/

 

I agree with Pyro however. A power adder would make a more streetable car at these power levels.

 

-Jason

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That Advanced Induction Site was helpful. I like the flow numbers they have on their heads. $1750 for heads that flow 278cfm isnt too bad! I know forced induction is the way to go but he's trying to keep the cost of the engine below $4000. He found an LT1 locally for $600 but it doesnt have any of the accecories, harness, pcm, brackets, or the MAF. So he has to buy all that stuff. He is planning on a PAINLESS harness, stock PCM, and either the corvette brackets or the camaro brackets which ever will fit better. He is also looking for a used aftermarket MAF to keep costs down.

 

He knows that he will have to buy some heads, a good cam, bigger TB, and some bigger injectors.

 

When I ran DD2000 I came up with this...

 

355cid, LT1 Heads by Advanced Induction(the flow #'s from their site), 11:1 compression, 58mm TB(1000CFM Sequential-Fire Injection), large tube headers with mufflers, ZZ3 cam

 

489HP @ 6000RPMs

481TQ @ 4500RPMs

 

 

What do you guys think of this combo?

 

 

Guy

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yes you can get an LT1 to make 500 flywheel hp N/A but it will not be very streetable, or cost effective to do it, mileage will not be good,and it will cost MORE than building equal power levels with a gen 1 350sbc.

once you place the goal to get close to 500hp and above 500hp consistantly from an engine of only 350 cid,N/A , youve limited options, unless your willing to either spend fairly large amounts on forged parts, that can handle the high rpm stress like solid lifter roller cams, and machine work , porting or better heads and intakes,to allow the engine to breath effectively at higher rpms or a power adder like nitrous. or you reconsider and go with a stroker kit to increase displacement .

most LT1-4 engines making a true repeatable 500 hp are either costing in the $6000 plus range or have larger displacement, or have power adders or a combo of those options simply because the stock engine is limited to about 1.2hp per cid without mods that quickly boost the price, displacement or use those power adders.

1.2 x 350=420 hp, one way or another those extra 80-100hp cost either lots of money or lots of time modifying stock parts

now Im not saying it can,t be done, or done cheaply, but it is unlikely to be done without one of the listed options

 

in my opinion your buddy should rebuild his bbc 427 and add nitrous and EFI, if done correctly he can get reasonably good mileage and make awesome power , yet still spend less than he would on the LT1 plus the mods and swap costs, a 427 bbc he already owns built and modified with the correct heads and cam,ETC. can easily produce better power than any 350/LT1 with the necessary mods plus the swap costs.

the bbc has better flowing heads

larger valves,angles valve heads

larger displacement,

much more potential

more parts available

stronger parts

 

now that being said , read this

 

http://www.phil.tobin.net/Hoover/top.html

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Guest Nic-Rebel450CA

I agree with Grumpy, build the BB

 

Bottom line is that HP is fuel. If you build a smallblock to make high HP, it will consume a lot of fuel. If two engines both are built to make about 500HP, they will both consume about the same amount of fuel. The only difference is going to be in the losses in the engine. The big block would be more likely to be able to make up for that because you can use bigger valves in a big block. Bigger valves means better flow and (ideally) better efficiency.

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Well the BBC 427 is in perfect running condition and it was rebuilt about 2 years ago but it only has a few thousand miles on it(under 10,000miles). Its just that he was offered $5000 for the engine so he wants to sell it. He claims that the motor is out of a 68' Vette and that he only paid $750 for it....I find that a little hard to believe? Arent the 427's a little on the pricey side? Either that or he got one hell of a deal! Either way the motor is coming out and its being sent over to Korea! :shock: He's really wants the BBC 502 but he doesnt have the ca$h to buy it. He really wants EFI and I dont blame him but I dont think hes going to be able to get the power that he wants for $4000. I think if he settled for the low 400's he could do it. Besides I dont want him to build a car that is faster than mine! LOL :oops:

 

How much boost can you run a stock LT1 with 10.5:1(stock) compression? I see in Summit and Jegs they sell superchargers for 4.5lbs of boost for about $2500. How much power can you get from 4.5lbs of boost?

 

Guy

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I agree with what Grumpy said. I believe the stock LT1 rods are rated to 450hp and 6500 RPM, so you won't get to 500hp reliably without rebuilding the bottom end. You'd also need to sink $$$$ into the heads, and this is a waste when there are better castings out there for the other generations of SBC. At that point, maybe you should consider a different power plant.

 

If you were to relax the 500hp target, I think LT1's are a great budget choice. I was only shooting for 400hp, and the LT1 seemed to be the cheapest fuel injected way to get there. Cam/valvetrain swap + good headers and exhaust, and hopefully I'll hit the target without touching the heads or bottom end.

 

Just a thought, but I noticed Trick flow released a set of heads for the LT1. They modified their 23* SBC casting for reverse cooling, and the heads produce similar flow numbers. They're not too expensive, and the combustion chambers are much bigger than LT1 heads, which should help your cause if you're going to try forced induction.

 

-Jason

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ok , your buddy wants to replace his 427 with a big blocks power but can,t afford the 502 and has approximately $4500-$5000 to work with as a budget, lets see what we can think up as a valid option

heres a valid choice simply because this engine with a cam change gets close to 475hp

 

http://www.sdpc2000.com/cart.asp?action=prod_detail&catid=120&pid=119

 

if your able to spend slightly more these options (below) may work as a starting point

http://www.sdpc2000.com/cart.asp?action=prod_detail&catid=514&pid=623

 

http://www.strokermotor.com/535SB.htm

 

if your really bucks down,

heres a new 454 with efi for $3500 you can use a http://www.bgsoflex.com/megasquirt.html

 

cpu and have a running EFI 454 for under that $4500 BUDGET

http://www.sallee-chevrolet.com/sales.html

 

NOW ill AGREE THAT IT WON,T HAVE THE SAME PERFORMANCE WITHOUT MODS BUT YOU WILL HAVE A RUNNING efi ,454 ENGINE WITH A ROLLER CAM, FOR UNDER $4500 AND MODS CAN BE DONE LATER

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Yeah well this whole LT1 thing is out the window! Yeah he got a call from the "secret service, FBI, and wester union" today. Apperently the guy from "Korea" really isnt from Korea and the check wasnt real! Let me tell the whole story....

 

So about 3 weeks ago this guy at work decides that he wants to put his "427cid BBC from a 68' Vette" up for sale on a Corvette Forum. So he does and he gets a reply early last week, from this guy in "Korea" that wants to buy the engine and he willl pay $4500+ shipping for the engine. So he said that he would sell it for that but he's only selling the long block...no manifolds, carb, or accessories. Well the guy said that was fine and that he would send the check ASAP. So he gets the check on Tuesday this week but the check is for $8000. Well this guy at work thought the extra money was the money for shipping. So he writes the guy in "Korea" and asks what the extra is for? The guy tells him that the extra is for shipping but if there is any "leftover" money that he should just send it with the "shipping company and they would give it to him when the engine arrives. So then this guy at work shows me all the emails that this guy has been sending him....he has sent him like 25 emails in the last week and a half saying that "as soon as you get the check go to the nearest "cash store" and cash it then ship the engine ASAP" he said this in almost every email. Then this guy at work said that he tried to get him to talk on the phone(he emailed him asking if they could talk about the details of the shipping just to make sure everything went right) but when the guy in "Korea" got that email he said that he cant call because "he is very busy with the recent death of his mother" Right then, when I heard that I started calling it a scam! I told him there is no way that anyone would say something like that for real! Its just to fake! So Wednesday he cashes the check at Western Union and then deposites the money in his checking account. Well then yesterday he bought an LT1/4L60e combo off of ebay for $1700 and today he brought $600 to work to go buy some tools at Sears. Well at about 1:00pm he started getting calls from the "secret service, FBI, and Western Union" saying that the check was not real and that he needed to return all the money! Yeah I was like "hey dont look at me I kept telling you that it was too good to be true!" So now he is out like $400-$500 due to the fact that it cost him $150 to cash the check plus he already spent some of the money. He canceled the order for the LT1/4L60e and he didnt buy the tools. He was actually planning on taking the motor out this weekend and shipping it on Monday! :shock: So he almost got royally screwed but instead he got lucky and they caught the scam in time! Here's the really funny part, and I do mean REALLY FUNNY part........the guys name from "Korea" was.........................................

Henry Smith!! :shock: :malebitchslap: :bonk::twak: How stupid can one person be? If a guy from Korea emails me and tells me that his name is "Henry Smith" and he can't even "write good english" then why would I believe that he's going to send me a real check?!!!!!!!!! GOD DAMN THIS GUY HAD IT COMING!!!!!! :bonk:

 

To say the very least the guy at work will be ripped on for a few weeks! We now call him Henry Smith! LOL ROTFLMAO!!!!!! :lol:

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