LT1 Build?
 

Well when winter rolls around I want to crack open the piggy bank and at least start building a motor... won't have it done for a while but I want to know what I should have budgeted to build it.

I'm looking for a low mileage LT1 that will just need to be lightly honed, don't want to waste extra money on boring the motor. I've never built a higher RPM motor, I've built a few with stock heads and mild cam/s but that's about it.

I'm not sure if the crank will hold up to my plans (so let me know), defiantly want to have splayed main caps though. I plan on running the stock crank or a comparable aftermarket casting, doing all new bearings and running some sort of 4340 rods and forged pistons (sit right around 11:1). Looking into Advanced Induction's 200cc heads and their 230/238 cam. I'm sure they'll match a valve train to my specifications. I would be having them port the intake manifold and obviously changing whatever I need to change (throttle body, injectors, tune).

AI claims the cam builds power to 6,300-6,400 RPM, I'd imagine it would hold power til about 6,700-6,800 RPM and would really sit high in the power band if it was spun to 6,900 RPM. I will have to double check on this but I'm sure on a stock CI motor it is more than capable.


Will the stock crank hold up to that kind of RPM? Obviously I'm not going to have this thing built very fast but I'd like to hear input. I figure even if I only set aside 15% of each pay check and go $1,000 out of pocket I could have the funding to gather all the parts within a year.

The stock crank is pretty strong and should be good for your set up if your on a budget. The AI 200cc package its awesome and proven to make big numbers (430rwhp on a stock short block and intake). The 230/238 cam is another good choice. I'm debating between that and their slightly smaller 226/234 for my build.

I wouldn't be too concerned with the crank but if you do want to replace it, go forged. Ohio crank, since you are on a budget, would be my choice.

I so love spending other peoples money! @$1,000 your probably run out of cash FAST!

Stock crank should be good to 500-550 HP and 6800 RPM. Don' go chep on the rods, I would look at lighter rods such as I~beams and also quality pistons, nothing cast / hyper types.

What year is the car? If it's a 93 you'll want to convert to a 94-95 timing setup = vented opti,timing cover and 94+ Opti harness.

Also at those RPMs I'd suggest going with a double roller timing set, over the GM LT4 or Extreem, that will also mean going with an electric water pump.

30 Lb injectors should be enough, 36s would be safer so you don't go high into the duty cycles, will most likely need to upgrade the fuel pump. You should also go bigger throttle body. Going to need headers / cat back so that it can breath.

As already said, you will need a good valve train. Go double springs, not beehives. You will also most likely need quality lifters. To spin an engine high requires some extra seat pressure to prevent valve bounce ( float ), stock lifter could collapse. hardened pushrods, quality rocker arms (I'd suggest Promags with GM guide plates)

Alright thanks for the information. I am putting aside $100 a week from each pay check until the winter rolls around along with the $1,000 up front. Should have $1,600 aside and I make descent money plowing to fund the motor even more. By the end of the winter I should have about 3-3,500 invested into the build.

$3-3500 is the perfect amount for a complete heads/cam swap with some supporting mods.

Sounds a bit light to me unless he already has some of these bolt-ons. He also mentioned refreshing an existing engine so the numbers below would be on top of that work.

$1500-$2k for heads/cam
$200 for ported intake
$300-$400 for injectors
$75-$100 for pushrods
$300ish for 58MM TB
$100 lifters
$100 in gaskets
$100-$200 for timing chain
$500 dyno tune
$400 headers/Y

let's not forget the incidentals.....

Note some supporting mods. You don't need a ported intake or tb. I was thinking headers and cai. I also meant just a h/c swap, not nearly enough to dwell in the bottom end!

Silly pal. Why would you run AI 200CC heads and a stock TB and intake?

Because you don't have enough monies?

HP gain with a ported intake is negligible at best - and the throttle body isn't a necessity but is certainly nice to have (HP gains of 10+ from 48mm to 58mm on a H/C setup).

You're definitely headed in the right direction using AI though. See sig.

I have headers/y pipe/full exhaust and moroso CAI; plan on gearing to 4.10's, strut bar and probably sub frame connectors in a few weeks.
I don't expect $3,000-3,500 to build the entire motor, I figure it will cover my rods/pistons/rings/bearings, intake porting, and cam/lifters/timing chain and close to covering most of my heads.
I'd still need/want injectors, throttle body, gaskets, electric water pump, tune, aftermarket ignition?, and whatever else I'm forgetting.

I figure realistically it will take about a year to build and I figure I'd have around 6 grand into it. Probably will change the clutch at this point as well so add $500 more. Plan on running rear til it goes.

I say 8 to 10k

Eh I'm usually pretty close with my builds but we'll see. I'm leaving the stock crank don't forget. On a very high end I'd call it $6,800.

any updates with this build? my suggestion, spend the money on quality stuff and upgrade, i did a simple heads cam build and got new everything up top but left my bottom end out and a year later i have a snapped connecting rod. now im doing it again but the bottom. this time around just for porting and machine work as well as pistons and rods im looking at around 2,500 with gaskets as well. last time around when i did the top end of it i was into the 4,000 range, that was without a dyno tune and i had the basic mods before hand such as headers and y pipe. definitely wait till you can buy the parts, dont skimp out, take advice from brian and adam and whoever will lend their 2 cents

If I could build a fully forged, Ported heads and cam LS1 motor for around 5,000 then I would think you could build a fully forged H/C LT1 motor for less!! Check on LS1tech for parts as people give up to soon and sell off there mods that they plan on doing. Thats how I got my parts.

I would double that, depending on the head gaskets then go even higher, I run commetics, they also required special machining of the block and heads and the gaskets were nearly $100 each.

Yah, hoses, belts, motor and trans mount can run the dollars up quickly.


Don't forget:

1) Machine work on the block.
2) Balancing rotating assembly
3) Fuel system / fuel pump
4) ARP bolts

Thik about the clutch, rarely can a LT1 fFlywheel be reused/resurfaced, and if you're making allo of power yu are going toneed a really good clutc. I run the street twin clutch = $1200

^^ good info and yes I did leave out the head gaskets which could double or triple that cost. I have a spreadsheet for all the costs that went into my build and I do not like looking at it. The incidentals alone were another $1,000+.

LOL! Honestly, I know what I spent on the 385 short block, but RALLY don't want to even think about how much total cost was Easy $10Gs!

Sounds about right. In porting alone (heads and intake) I have 1700 into it..

I put it on hold until after the winter... didn't feel like spending $300 a month to insure something I wasn't driving. Bought a V1 Vortech (t-trim), walbro 255 pump and then stopped there. Planned on buying a water kit this week but I'm busy with work and think it's just going to all have to wait til after the winter. I can't leave it motor-less in the driveway when the snow arrives.

In all honesty, it's not my number one priority. It's my summer cruiser and summer is just about over. Debating on burning some money on another toy instead.

Found an 8.1 Vortec motor with the harness on ebay for a fair price (been eyeballing it and debating if it's worth me attempting to tackle splicing harnesses -- which I have never done, my buddy also is willing to get rid of a 88-98 half ton 6" lift pretty cheap. Coincidentally I have a Z71 that would love the attention and be drivable in all weather.


After the winter I will resume the project. Just going to pull it all apart, check the bottom end, bearings, and cylinder walls. Heads will be going to LE, will be having a cam ground by him as well, and running forged pistons/rods with 6-7 PSI. Plus my mom would kill me if she found out how much money I've already invested in the car lol. (In two-three months I've spent well over $3,000).