Engine choice?

[Medicash]

Hiya, I was wondering if i could pick your brains, I have a 1977 C3 corvette with a smokey engine (numbers matching)now the choice is do I spend money on a rebuild, or do I buy a rebuilt LT1 Small block with the following

LT1 block
4 bolt main bearing crank
Big journal Crank
Full engine balance inc flywheel and new clutch
Heads ported standard valves
268 competion cam hydraulic lifters
Roller valve gear
Torker 2 inlet manifold
Holly 750cfm carb vaccum secondary
4 branch s/s headers
Mallory duel port distributer
Edlebrock high clearance rocker covers
High volume high pressure oil pump
Steel duplex timing chain and gears
Chrome sump
Chrome timing case
Short water pump
Aluminium belt pulleys
Chrome air cleaner


This engine also comes with these spares

2 big valve heads not ported
1 pair of moroso rocker covers
Spare carb
Low mileage cam followers and gear


It has never been run since its rebuild.

now I know nothing about engines so I don't know if the LT1 has all the bits to make a fab engine,or what the power output would be or the fuel consumpsion would be, the LT1 is for sell for £2,000 in the UK, your thoughts would be very much appreciated.
many thanks in advance
Jerry

 

[Scott Winebarger]

Its all according to what you want to do with the car. For me, I would pull the original and spend whatever it costs to rebuild it and leave it as near stock appearance as possible . Wow , I can't believe i said that , just a few years ago I would have slammed a blown big block in it . Its a toss up , I have the correct engine minus a little metal on the heads and a cam change.

 

[lnirenberg]

I assume you are talking about a C3 LT1 and not the newer vintage. If you can confirm the engine's bona fides and it was rebuilt by a reputable shop, the equivelant of $3500 US seems like a good buy. My guess is if you pull your engine and rebuild it to anything approaching the spec and power potential of the LT1 you will likely spend more. My only concern about the
LT1 is its vintage more specifically if its an earlier high compression version did they harden the valve seats so that you can run pump gas (I assume your super is the same as ours) without doing damage. If all checks out, put the #s motor in the garage and go have fun.

 

[Lucy64]

This seems to be a great deal for an LT1. How long ago was it rebuilt? A friend recently obtained a real Boss 429 Ford motor that had been rebuilt many years ago but never run. I dropped it into his 39 Ford and within a couple of months he started having major problems with it. Now he has a very expensive rebuild on his hands. If this is truely a good running LT1 this seems like a great deal and I would get it and store the original numbers matching motor for a future rebuild and run the hell out of the LT1.

 

[Vettehead Mikey]

LT1 is its vintage more specifically if its an earlier high compression version did they harden the valve seats so that you can run pump gas

Hardened valve seats are completely unnecessary for Corvettes - they don't run under enough load.

 

[lnirenberg]

Unless Medicash is a little old lady or in any case drives like one, which I can't imagine given his(hers?) pursuit of such a performance motor, a non-computered, carburated 11:1 compression ratio engine driven with any "reasonable" amount of pedal will have issues if run on modern pump gas--caveat being I assume that the UK pumps the same sludge as we get in the states. Hardened seats will add some durability. Its not an issue I deal with but solely my opinion. Petty squabbles aside, if it is a quality build it seems like a good value for a kick a** engine.

 

[Vettehead Mikey]

Hardened seats will add some durability. Its not an issue I deal with but solely my opinion.

Opinions are nice, but historical facts speak louder. There's never been a Corvette that needed hardened valve seats. Unless you're driving a loaded dump truck up a hill at full throttle, the valves and seats don't get hot enough to warrant the hardened seats.

Additionally, there's always the possibility of messing up a perfectly good set of heads by machining them.

You seem to be mixing two different issues- high octane gas and leaded gas. The poster may need to use high octane gas to avoid pre-ignition, and leaded gas may be the best way to solve that but there's no need for lead to help the valves.

Might be a petty squabble to you, but giving someone hard advice based on uninformed opinion serves no purpose.

 

[Medicash]

Hiya,
The above engine was originally out of a 1972 corvette. Its last home was in a road going racing car (Ultima) when it had oil problems, then it was completly stripped down and rebuild with all of the above.
It was rebuilt about 2 years ago and has never been run since,the present owner said he will check it all out, ie: remove the sump etc and help to install it for me, he paid £1000 for the motor and spent another £1000 on it so his labour is for free. is it a good speck motor or has he missed anything? would it be alot quicker than a standard 1977 small block?
I don't drive like a little old lady only because I am the wrong sex and not that old ! lol

 

[Vettehead Mikey]

I'm not sure that the intake, carb and aircleaner would fit under your hood. Sounds like too much carb for the street also.

 

[Kid_Again]

Believe me, I have Been There, Done That

I drive the absolute crap out of my cars and both engines needed to be rebuilt. Not a surprise. The saddest day of my life was rebuilding my existing #'s match engines. Long story but I was screwed by the engine rebuilder and now my #match 427 block is scored and sits in the basement. I swapped in a new crate engine and would never rebuild an engine again.

My advice is to be ABSOLUTELY certain that you can get your money back on the new engine if there is any problem at start up. Pay attention to rough running that doesn't respond to timing changes, abnormal and/or consistently high engine temps (it IS a newly rebuild engine so expect it to be tight and hot the first time) and low oil pressure.

The price sounds decent to me. I agree the carb is a little on the large size for this street setup (the cam is not outrageous). Is that manifold a single plane? I think it is and if it is, then I agree that the induction system is oversized for the street. It will be a pig right off the line but it will kick ass over 2500r's. If it were me, I'd keep the carb and go to a high rise dual plane manifold, if possible.


Carry on, good luck.

 

[Medicash]

Thanks for all your comments so far.
Is there anything else I should ask the owner of the LT1 engine that would help in my decision?

 

[lnirenberg]

Opinions are nice, but historical facts speak louder. There's never been a Corvette that needed hardened valve seats. Unless you're driving a loaded dump truck up a hill at full throttle, the valves and seats don't get hot enough to warrant the hardened seats.

Additionally, there's always the possibility of messing up a perfectly good set of heads by machining them.

You seem to be mixing two different issues- high octane gas and leaded gas. The poster may need to use high octane gas to avoid pre-ignition, and leaded gas may be the best way to solve that but there's no need for lead to help the valves.

Might be a petty squabble to you, but giving someone hard advice based on uninformed opinion serves no purpose.

As this part of the discussion is likely moot given the vintage of the engine, I apologize in advance for hijacking this thread or at the very least getting it a bit off course from the direct question as to the attributes of a specific available engine. I do so, however, only as I find myself in a corner with a large vise wrapped firmly around my gonads and therefore am forced to defend my manhood lest the screws get tightened to an unbearable level , at least in the metaphorical sense of course.
Although they use a different method for computing octane ratings in the UK, its my understanding that their premium is roughly equivalent to ours. As you stated, I did mix together the facts that lead was a valve lubricant as well as an octane booster. I did so for the sake of brevity as that was really not the point. Un-leaded gasoline does not offer the lubricating qualities of leaded fuel and, in pre-catalytic high compression engines designed to run on leaded fuel, will eventually cause valve seat recession. Whether this is at 20, 40 or 60,000 miles or more depends on one’s driving habits but in any case the engine will begin to develop valve seating problems sooner than if it were run on leaded fuel. This potential damage can be dealt with in several ways and combination of ways, of which a few that come to mind are--living with the inevitable early tear down, which sucks; retarding the ignition and not driving aggressively, which sucks; using a lead additive, which I have no idea if it is available in the UK, or; using hardened valve seats. I did not intend to introduce this concept as a point of contention but only one of many things to consider when looking at this specific engine in the context of on the ground reality in the year 2006. Mea Culpa if I was not clear, but my only real point (granted in hindsight) was that a pre-computer, carbureted, high compression engine designed to run on leaded gas will be less durable on modern pump gas.

 

[Vettehead Mikey]

Mea Culpa if I was not clear, but my only real point (granted in hindsight) was that a pre-computer, carbureted, high compression engine designed to run on leaded gas will be less durable on modern pump gas.

And one more time before we all die of boredom, the above is all great 'the sky is falling' theory, but in practice no Corvette has suffered valve seat recession due to the use of unleaded gas.

The big panic in the 70's on this issue when unleaded gas was introduced turned out to be a non-event for 99% of cars.

 

[lnirenberg]

And one more time before we all die of boredom, the above is all great 'the sky is falling' theory, but in practice no Corvette has suffered valve seat recession due to the use of unleaded gas.

The big panic in the 70's on this issue when unleaded gas was introduced turned out to be a non-event for 99% of cars.

And, only for the record, I respectfully disagree.

 

[Bob Chadwick]

Let's get back on topic guys. Medicash wants to know about the engine.

If you want to debate this issue please start a separate thread. Thanks.

 

[Medicash]

Thanks for the info and opinions on the valve seats from both Inirenberg and Vettehead Mikey. as Bob mentioned it would be good to find out more about the engine described above and your opinions on the usability of the engine, are the components mentioned compatible with each other or are any of them unsuitable for a road going car? As i know nothing about engine rebuilds and suitable components I am kinda relying on info from you guys and gals, how important is an engine matching numbers car? The car was White when it left the factory, it is in the lengthy process of being stripped of all paint for a complete respray, in either Metalic Blue, or possibly Black.I don't think the wheels are corvette, so the car has a few none original bits, If engine matching numbers is something I should really keep, then perhaps I should not go for the LT1, but if this is not important then the LT1 may be on its way into my car. Did anybody have there motor rebuilt to a similar speck and what did it cost? Once many thanks in advance for your help. Jerry

 

[Vettehead Mikey]

In looking over the engine specs again, I'm really not sure why the seller is claiming it to be an LT1 engine. Most of the components are aftermarket street/strip/custom stuff and are not equivalent to an LT1.

If the block came from an LT1 car, then it's of no added value to anyone except the owner of that same car. LT1 blocks are the same casting numbers (3970010) as all other small blocks, nothing special or different.

All this to say that this engine should not be viewed as a gen-yoo-wyne LT1 engine that is about to be transplanted to a later car.

I'm not well versed enough in aftermarket stuff to know whether this would be a suitable engine for the street. One thing not mentioned is what type of pistons are fitted and what compression ratio it's running at.

 

[Koop]

If you aren't going to build it yourself and you want to have confidence take look at these: My favorites small blocks are the ZZ4 & ZZ383! These two make everyone drool, most important you will drool on it!

http://www.gmgoodwrench.com/perfpartsjsp/partlist.jsp?section=ce&cat=9274

 

[Medicash]

Hi, I have just spoken to the owner and found out that it has TSW pistons in it and it is running at 9.35 to 1. what does this mean? is it good news or not, and that he will accept £1,500 for it!! he will also help with the install.The engine came from a 1972 corvette, then it was put in an Ultima (road going race car) the engine was put in back to front in this car and the owner of the Ultima was trying to see how fast off the line it was, all the oil was driven to the narrow end of the oil pan and away from the oil pick up causing the crank to seize up, the engine then had the above rebuild using the existing pistons that had only done about 1,000 miles,the crank was reground but all the other components were new.