Im about to swap a B body LT1 in my 92 Z28 while the engine is out I want to put some parts like .030 pistons,cam shaft and stock aluminum heads about the pistons I cant find LT1/LT4 pistons but I was told in Thirdgen.org that the old chevy pistons will fit but they are heavyer and I found Speed pro pistons they got alot of pistons but I want to raise the CR the stock CR is 10.5:1 is that right? If I want to raise the CR do I need to use dome pistons? are these gonna work (http://store.summitracing.com/partde...0&autoview=sku or http://store.summitracing.com/partde...0&autoview=sku ) I got no experience about pistons so I need help with this and about the cam shaft I will go with CC306 and dual springs,about the heads they will be stock heads I will port them and it will be a carburetor engine not FI I guess 650cfm is enough I will finish the set up with LTs,3.73,3000 stall(or suggest the best stall) I got another question is the 700R4 will fit direct to the LT1 or not?if not what do I need to do to make it fit?

 

Why a carb? You're about to ruin one of the best parts of what makes an LT1 an LT1, the FI setup is where it makes the most of the HP and torque settings by letting the PCM make all of the adjustments.

 

It's cheaper to go FI than it is a carb in this case. You have to find an lt1 carbed intake and find a way to control spark. Then you have to run a low pressure fuel pump for a carb, etc, etc, etc.

 

The 700 bolts right up, might have to play with the TV cable mounting. I'd run a 750 cfm carb if I were you, but I haven't seen a good aggressive carb intake for the LT1.

 

Guys I found the engine for free with GM intake manifold to convert LT1 to carburetor so why all the fuzz? I was thinking of making it fuel injection again to play with the PCM but maybe in the future I will convert it back to FI right now I will run it carb and play with it if I like the power I will stay carb if not I will fuel inject it again

 

OK, going with a carb rather than EFI is a big step backwards in terms of driveability & mileage, but it's your deal.

As for choosing pistons, etc, you REALLY need to work with the guy at the machine shop - you can get "internet advice" until it runs out of your ears, but the machinist has two BIG advantages -

1) You can generally figure that he knows what the hell he's talking about (which you can't always say about "Joe Schmoe" on the internet),

and

2) He actually has his eyes on YOUR engine.

But, like I said, it's your deal...

 

Thank you V8 Rumble the mechanic that will assemble my engine is very good but I just want to know which pistons to go with if it was flat top : 2 valve reliefs or 4 valve reliefs? can I use dome(dome height 0.125) pistons? about the heads and all that is not a problem

 

If the cylinders are not in bad shape and don't need to be bored, I would not swap the pistons. They were lightweight Hyperutectic pistons from the factory with powdered metal rods and with the stock crank, I have seen LT1s turn 7k rpm on the stock rotating assembly time and time again. 10.5:1 is a really good CR to run on these motors, however I would look at one of the newer XFI line of camshafts that Comp makes instead of the 306, the 306 tosses the power band way up on the RPM range (one reason a local guy was turning his to 7k) it comes in around 3500-3700 and keeps pulling until you stop, the XFI cams brings the power range back down on the scale coming in sooner and pulling to about 6300-6500. Also, don't forget to swap out rocker arms and valve springs as well.

If you're going to have to bore it, might as well take it and make a 383, yes a little more money but the crank in the LT1 would probably have to be balanced again if you swapped the pistons to a different type due to the crank being balanced for the lightweight pistons.

 

The engine from B body (impala 95) Im afraid that the engine is tired thats why I want to change the pistons and while Im at that way raise the compression a little more,one of the replys a member told me that if I use the stock head gasket from B body engine with aluminum stock heads will raise the compression more is that true? and Please feel free to give me links about the XFI cams

 

First I would like to say, plenty of guys have put carbs on their LT1's and havn't looked back(mostly because their setups were radical but others for the ease of tuning carbs). Either way, I say its your car do what you want with it.

Yes, the stock CR on B-body's were 10:1 and F-body were 10.5:1 (smaller combustion chambers on the Aluminum heads). You are correct about LT1 pistons being lighter, the bob weight of the crank is a bit different than the Gen 1 setups. Either way, I would get my rotating assembly balanced if you swap pistons. Just remember that if you get it internally balanced, the LT1 is externally balanced in the back... meaning you will have to buy a neutral flexplate/flywheel if you get it balanced. Im using the 306 cam aswell(but with stock short block and LE2 heads). That cam works with a higher stall than 3000, most people run a 3600 stall with it because it will want to spin up to 6500. I used the 10308-1 Springs. They are nice budget springs and will handle the 503/306 cams.

However, I would talk to someone about your compression and the cam you are using. Since I do not know how high of a DCR you can go on a carb'd LT1 I will say this, Im running 11.10 SCR with the 306 cam and my DCR is 8.25. Make sure you check your DCR and not just your SCR being that you will be carb'd. When you use a calculator to figure out your DCR the 306 cam has a ADV Intake Closing Angle of 73.

Edit: 700R4 can be used but you will need to buy a bracket for the TV cable because the 4l60E is electronically shifted by your PCM. I know some aftermarket throttlebody's come with brackets for either th350 or 700r4 but Im not sure how that works when you go carb. Someone else might be more of help with that.

Goodluck

-Russ

 

Head gaskets are the same between the two heads. I believe the chambers on the iron heads are a tad larger, thus the difference in the CR.

http://www.compcams.com

and do a search for XFI

 

Iron Head(B-body) had a .029 Head gasket where the F-body(Aluminum heads) was .039 or .049. I forget which but It is bigger.

 

Felpro part number for Impala SS 9966PT

Felpro part number for 1995 Trans Am, 9966PT

 

That gasket is the newer one, not stock. They also sell Victor Rienz Nitroseal 5898 at napa its .026 also not factory though. Let me see if I can dig up the factory part number.

Edit: 12553160 is the factory head gasket.

 

Head Gasket Thickness
Stock gasket = 0.040
Fel Pro 1074 = 0.039
Impala = 0.029
Mr Gasket 5716 = 0.026

Found this on http://www.lt1engine.com/

 

Yep those are the correct specs. Alot of people have had trouble with the Mr. Gasket .026 ones thought. The composite comes off because the packaging was to tight. The Victor Rienz Nitroseal 5898 are the same exact ones(Mr. Gasket put them out under that name for some reason) but the packaging is a bit more loose. Napa discontinued them a few weeks ago but I got mine from cnc-motorsports about $15 per 1.

 

So guys do you suggest that I use Impala head gasket when I put the aluminum heads? I think I will stay with the current pistons for now just get the cam along with springs retainers and get a carb is 670 enough? or should I get 750-770 Holley?

 

I agree with Klortho, if the cylinder walls and pistons arn't it bad shape, just leave it as it is. I'm using the stock short block and will be expecting close to 400rwhp... but I also realize it wont spin to 6500 and last 150k miles. Id suggest do the cam/springs and then the heads when you get a chance but maybe start putting some aside for a short block rebuild in the future.

/shrug, Im not to good at carb sizes. I know their is a way to estimate it but I forget how. I think I have it in a Techbook somewhere, Ill try to get back to you with that if I find it. You should be able to find some good info on carb sizing with a search though.

Edit: oh yeah and depending on what CR you want, the impala gasket can be a nice way to bring your quench closer to where it should be if you arn't milling the block. My deck height was .028(yours may be different, as they are not all the same) and with .026 gasket brought me alot closer than the .039 did. The only problem is the gasket that is for the impala's, is for iron heads, because aluminum expands more than iron heads you could get brinelling from the head, scraping the gasket everytime it expands. The gaskets mentioned (5898 and 5716) say that it wont happen on that gasket but I wont know for sure until it has been running for awhile.

 

Genhero 400RWHP? dont kill me man what are the mods?

 

Nothing special, High 10 seconds is my goal but still wanted to be able to have fun driving it on the street, so I did some research and found the easiest way. LE2 heads/cam with supporting mods(Ported Intake, LT's, 3600 stall and 30lb injectors) would put me in the 400rwhp area. I decided not to go with the LE2 cam so right now Im talking with someone that is selling me a custom 306 cam, same specs but the ramps arn't as aggressive so they wont slam my valves closed(306 cam is fine though). I will be using 150 shot of nitrous to put me in the 10.9x/10.8x bracket then Im selling the kit back off. It should be ready to run in a few weeks, the wiring is the only thing that Im waiting on. Alot of members from a different forum have hit 400rwhp+ with that setup and hit high 10's with 100-150 shot of nitrous, so I just went off that.

Hopefully next year I can afford a new short block preferably a 383 but college is making it tight.

 

Thats something a 400RWHP I want the same in the future lol can you please give me a link for those LE2 heads

 

I dont know if I can post other people's website so I PM'd it to you.

 

Thank you man they got great stuff do you know the LT1/LT4 guys in my country suffer because they dont find good stuff for LT1/LT4 I will call my friend later and tell him about those packages I bet he will order heads/cam in next week

 

Lloyd's site is here

www.eportworks.com

 

He changed it. This is his site now.

http://www.elliottsportworks.com/

 

Do I need to send him my stock heads to get that heads/cam package for that price 1,750$ ?

 

Yes

 

I asked for the Victor Rienz 5898's from NAPA and they gave me these:


I asked them what the thickness was on them & they said they didn't know; does anyone here know? If these are wrong is anyone still selling the Victor's (.026)?

 

9966PT are the .039

Those are the newer Fel-Pro gaskets.

 

CNC-Motorsports.com still has them. It looks like NAPA stopped carrying them. The link to Victor Reinz gasket...

http://www.cnc-motorsports.com/produ...D=20111&CtgID=

You will need a quantity of 2 since there is only 1 gasket per pack.