Hi,
I have a 1995 coupe. It has 95,000 miles. I've been thinking about the lt4 conversion kit, but I'm worried about the high milage I have. does it make sense to do the conversion?

 

"LT4 Conversion Kit"....is there such a thing? I was thinking about doing the same but I thought I was going to have to buy parts one by one. Tell me more.... Thanks

 

search the archives. theres tons of info on what the LT4 is. basically, better heads, raised runners, bigger valves etc.. for 30 hp... you could take a dremel to your heads and get 30 hp. trust me on that one... its been done... the cost/performance ration isnt a good one at that. remember that ain engine is an air pump. if you port your stock heads and drop in a mild cam it will do a much better job of pumping air in and out of an LT4, which usually means much more power.

 

Better route would be to have your heads sent off along with your intake and port matched to about stage II flow. Add a 52mm throttle body, 30lb injectors, AFPR, 1.6:1 ratio roller rockers, long tube headers such as Exotic Muscle's LT1/LT4 custom fit headers, and a Corsa Power Pulse Catback exhaust. Then take it to a dyno where they can tune and get a dyno tune on the PCM to zero-in the power. Should net you about 400hp at the crank.

 

with that mileage, you spin a bearing after the cam swap. leave it alone. do a search for spun bearings.

 

Dont do the head/intake conversion, just do the cam change and have your current heads sent off for porting, youll come out better in the end.

 

If we learn anything from history, it would be that you should focus on the lower end before you improve the heads and cam. A good move might be to go with a 355 (just bore) and rebuild the lower end and then go with your LT4 conversion. But as said earlier, You can get more for your dollar by sending your heads out. Besides, who wants a red intake? You might also check this site out: www.moreperformanceinc.com Look under packages.

 

Me!!! It depends on what your overall goals are for the car I think. If you are simply looking to boost power a little go with porting your stock heads and a cam swap. If you think someday you might build your bottom end to a 383, 396 stroker with say a BIG ROLLER then go with the LT4 Heads now or even some AFR's. I would have them ported as well. I have stage 3 LT4 heads on my stock bottom end 350. With a decent cam.

But the most cost effective way would to be getting your stockers ported, I think there is a Group Purchase in the c4 parts section right now on ported heads.

 

First off, the LT4 heads are a better platform for future enhancement than the base LT1 heads are.

Also, the package is complete, with built heads, intake, gaskets, most everything needed for under $2200.00 from Skoggins Dickey.

Oh, and the gain is more like 60hp.

I would rebuild the bottom end tho, at 95k miles, it will last long for it.

 

Hey 1995-lt1
Having your heads ported & a good 3angle valve job is a great place to build a good foundation for all your future mods and add real horsepower. Let's look at your application & goals & build toward them. Check me out at www.steadfastperformance.com, maybe I can help.

Greg

 

Personally if it were me at that milage and at the amount of work its going to take to do the conversion. I would go ahead and pull the engine out, and have the bottom end rebuilt with some good parts. Not necessarily do a stroker but depending on your budget, I would at least tank the block, replace the bearings, polish the crank, check the rods and pistons and ring it. If the bores are ok and if the pistons are ok then just hone it and ring it. If your budget has fat in it then throw in a balance job or if your pockets are really deep then do a stroker I too would go ahead a have the new LT4 heads CNC ported, and choose a better (bigger) cam, as there are others out there that are better now. But if you want mild performance, drivability and emissions then the HOT cam is not a bad cam at all.

I also think that the cam - bottom end failure thing is a myth. People have been camming small blocks forever. And after all a LTx engine is basically just a small block. I beleive that the main failure is that people are getting some foreign material (dirt) into the engine causing these bearing failures. I have seen shop guys using these rotary scotch bright pads on their die grinders to clean off gaskets from intake surfaces and other engine parts, these scotch bright pads along with the newer rubberized finger type abrasive devices for die grinders or drill heads all contain aluminum oxide or other abrasive compounds. When used with a die grinder thats spinning around at 10k RPM and slinging gasket debris and abrasive material around, where do you think all that dirt and grit is going? If that stuff gets into the lifter galleys and into the oil pan, the end result isn't going to be pretty. A friend who owns three repair shops has had a few engine failures due to this and he forbids his guys from using any kind of abrasive style gasket remover unless the part is totally off the engine where it can be washed clean.

 

The lt4 kit advertises 425hp at the crank, and you can mod that for even more

 

That # is from some tests that were done, but it is gross HP (no accessories) and they also used LT headers, RT cats, and a 52mm TB.
Check out the More Performance site for a CHP article on this.

 

If your engine is in good shape, I wouldn't worry about the mileage. I did a port and polish, camshaft, and electric water pump at 100,000 miles. I was amazed at how good the engine looked inside. I could even see the factory hone job. I use synthetic oil and change it about every 10k miles, and I don't use one drop of oil between changes, and my oil pressure is very good. If your engine is smoking, losing power, clicking, tapping, losing pressure, or you need to add a lot of oil between changes, of course you should rebuild. But if it is running great, I don't think a few mild performance mods are a problem.

 

with Vader86 , Bogus and TJWong on this. All are good posts.

 

Here you are http://www.gmpartsdirect.com/results...ber=pk12550630

 

I see your point on the D.I.Y. approach, but the trick is knowing where and how to grind to get that 30hp. I have many a good part-turned doorstop. Jim Pace chevy and Soggin Dickey Parts Center both sell the LT4 kit. Let us know how it turns out!

 

Save your $$$$ and have the bottom end done at the same time.

 

sell the 95 & buy a NEW Z06 in the spring...550hp

 

The conversion kit comes with the LT4 Hot cam Kit as well. That'll net you more than 30 hp. The whole kit is cheaper than a set of AFR heads so it's not that bad of a deal for $2k