Rebuild w/ extras
 

Hi guys,

It may be time for a rebuild on my '95 LT1 and I'd like to keep the original engine but rebuild at least to LT4 specs. Some mods as well, but I'd like to finish with at least 400 hp at the flywheel. Any suggestions would be welcomed. I have not done any mods on my cars in alot of years, my last being an original '70 LT-1 in my '64 Chevelle SS 'vert. many moons ago!

400 flywheel hp can be had pretty easily without going to LT4 specs (intake/heads/cam). You can do it spending less money or similar money and get better results. For what its worth, my mods are coming off my car in a couple of weeks and will be for sale. Less than 10k miles on all the performance stuff.

How is the bottom end? How many miles on it?

Only real difference in LT1 vs LT4 would be 4 bolt vs 2 bolt straight main caps, the heads and intake were different, but money could be spent on porting LT1 stuff with much better results.

What do you mean by full rebuild?

i'd start talking to local engine builders for the bottom end. keep the stock crank. then look at lloyd elliott or advanced induction for the top end with a small cam.

There are some minor differences in the LT4 rotating assembly but none really worth mentioning.

400fwhp can be easily had without touching the heads. I would go with an AI cam and cam kit, stock reconditioned crankshaft and rods and a good Mahle piston (hypereutectic would be fine in this instance). Have the cylinders bored .030" to clean up the cylinder walls. Add on top of that a good mail-order tune and a set of headers (I don't see them listed in your mod list) and you'll have a strong running car. :)

Thanks for the ideas. The bottom end seems fairly healthy but oil pressure is reading low (20 at idle, sometimes lower), so I think it's time for top and bottom

That's pretty good if that's a hot idle pressure.

Also plan for supporting mods. Torque converter as well as chassis and suspension mods could go a long way to make the car drive and feel a whole lot better.

Nothing wrong with 20psi oil pressure at idle. Even 10psi is fine. GM spec is actually only SIX psi.

you would feel comfortable with your car at 6 psi hot if it was higher than that before? i sure wouldn't

Yeah, if you have been staring at the gauge for years and the operating numbers noticibly change I'd be a little concerned.

With the money you are going to spend on the LT1 and since it sounds like you will be pulling the motor and taking it to a machine shop why not drop in a LS1 and do a mild cam in that? Just saying. It will probably cost the same to get a used LS1 and mod it as it will to rebuild you motor and do the mods you want to do with it. I love my LT1 but if I wanted to do a build on it I think the way I would go is do a LS1 swap since they are so cheap now to purchase. Just my 2 cents.. Not trying to start a LS1,LT1 war..

You really want to start with determining how good the shortblock is. Even with good oil pressure that's not telling you the condition of the rings and cyclinder walls. Normally if you know the engine has been taken care of you sould be fine with an engine under 100K, but if your not the original owner and the history is unknown you are going to want to at least be ready to freshen up the bottom end, rings, bearings, upgrade bolts and oil pump. You could at least do a leak down test.

Don't assume oil pressure means the rings are going to handle the extra cyclinder pressure a heads/cam is going to add, or that the bearings are good enough for the extra RPMs you'll need to spin the engine to make that 400HP number ( if you really want 400HPs). That's a bit more then doing something like a 305 cam, 400HPs is going to need a 306 or better cam, that means spinning over 6500 RPMs.

Also as a reminder check your budget, rebuilding a LT1 is going to cost more then your standard SBC. Gaskets, timing chain sets, hardened pushrods, etc all needed. 400HP can be on the edge of the stock fuel pump and injectors as well. So make sure you plan this out. Nothing worst then running out of dollars in the middle of a project.

she wants 400 at the flywheel, thats more like a hotcam or cc305.

Stock flywheel hp is 275.. So She needs to pick up another 125hp to reach the goal.

A camm'd LT1 can easily hit 400fwhp.

So a lt1 with just bolt ons and a cam can make 350 rwhp? If so let me know how so I can look into doing it to my 95.

I made 297 rwhp (depending on how much you trust the dyno) and I am on stock manifolds and cam. I don't think it's insane based on that or a lower number for a cam and bolton LT1 for 350 rwhp. Plus, he's saying 400flywheel hp, not rwhp

Yes but 400fwhp is around 350ish to wheels..

Yes, I just wanted to make sure you saw what he said. That's all :wink:

I'm at 380rwhp missing a few bolt-ons actually. Plenty of cams to choose from and bolt-ons would be all the ones you would expect.

On stock heads and stock intake?

I am just looking at a cam only with bolt ons. I dont see it worth buying a set of heads and intake for 1500.00 or more when you can get a complete used LS1 for the about the same.. Now if I can drop 1000.00 or less for a cam, bolt ons and a tune and make around 400fwhp then it is worth it to me to mod my LT1. If not I am probably going to leave it stock or do a LS1 swap into it.

price it out and see how you feel. figure a cam is around $300, whatever bolt-ons you want, and whatever little bs will run. then figure the same plus an ls1, accessories, lots o little things, computer, trans, harness, etc. its your car and either will go fast.

Heads are stock replacements from Edelbrock with no work done to them. Same size comb. chambers, valves, etc with the only benefit for more material if you ported them. Flow numbers are very close if not identical to stock.

Regardless, a cam only car with supporting mods can do 350rwhp without much trouble. More with a more aggressive cam.

Swapping to a LS1 is not always practical. You need the supporting parts to make it all happen which are not all that cheap (harness, computer, k-member, etc).