Hi all

in have a 71 4 speed that we're rebuilding it stock standard but im considering a crate engine replacement. My question is, not being that mechanically minded is are there any guides to this process? For example can I just replace the engine will i have to upgrade transmission, etc.

 

It depends on what crate engine you get. If you get a nice 300hp replacement crate engine you should be fine. However if you step up to a 427ci 500hp engine you may be looking for trouble.

 

 

I would make sure you stay with the same engine family. Big Block Small Block changes will need a lot of other stuff (suspension, etc). If you don't go too wild you can make minimal upgrades. If you go a little nuts like Scott did here - https://www.corvetteforum.com/forums...-corvette.html Then break out the credit card!

 

Hey I resemble that comment.

If you want to keep the parts around it, keep it close to that same you had before. Half the cost of my engine upgrade was because of the extreme engine I went with.

I went with Blueprint Engines. Looks like a great engine although they changed a few things from the description that pissed me off. We are starting it tomorrow. If it runs like I think it will, I would totally recommend them.

 

Being a 4 speed no matter what engine you select you need to look at the clutch before you re-assemble.

While the engine is out a lot of people replace the clutch at that time as well.

But if money is not the issue, I would start thinking about what power level will you enjoy with the swap.

How will you use the car.

1. Slow street driving ( 4 cylinder driving style ) = Stock power
2. Like to hit WOT for a 2-5 sec straight line = ~ 300+ HP
3. Like to hit 100MPH with WOT = 400+ HP

Then you can determine what else needs to be done.

See if you can find some local corvette guys and take a ride in their car a see if you like the response.

eg when I did my 78 L48 I was looking to match my 2010 Grandsport. I ended up with a ZZ383 and a 6-speed.

1/4 mile times

2010 GS 12.95 sec
1978 13.18 sec

Turned out very close for me.

Of course now I would like more power

 

 

This is good advice.
Make sure you know what you want and talk to someone who did the same swap so you know how it will fit if you change blocks. My engine turned out to be a Mark VI block instead of a Mark IV block. When you combine that with the aluminum heads I got I ended up having to switch to a hydraulic clutch and electric fuel pump unplanned. Luckily I was planning on ditching the vacuum system already because the wiper door actuator would not fit now.

 

Does that setup actually fit under the hood, with the manifold and air cleaner being so tall?

 

I am wanting a crate motor myself.do think that blueprint was the best buy for the dollar?

 

When picking a create motor, look carefully at the type and brands of the components they use.
I would pick new over reconditioned blocks and rotating assemblies.
Depending on your horse power needs, make sure you are getting new forged Pistons, rods, a new cast or forged crank.
Make sure you are getting good quality components from the carb through the oil pan.
Even if you are looking at a mild horse power increase or none over stock make sure they stand behind their product with a good warranty.
If you have limited skills, have someone with experience help you, don't rush, and take a break to get any questions you have answered by a professional or get help here on the forum.
Good luck, have fun, take a bunch of photos and post them here.

 

I decided on Blueprint for several reasons,
1) I liked the packages they had
2) For the price, the components were very good
3) They were the source for most of the companies like Summit, Jegs, and others.
4) A 30 month warranty sounded good.

The engine started on the 3rd try. Runs great. I have full Dino results.
My only complaint was that they had some mistakes on their website descriptions. They said internally balanced and manual fuel pump. Neither were correct. Luckily I had talked to them and knew it was externally balanced. The fuel pump was an irritating surprise.

All in all I am happy with it. It runs great.

That is the first running of it.

 

Thanks for the video, she sounds plenty healthy!

 

Let's see ... the stuff I've had to think about for mine:

1) If you are keeping your existing accessories and brackets, ignore this. Crate engine accessories come in hundreds of different configurations. Many configurations won't fit under the hood, will hit the control arms, the front cross member, the radiator and/or shroud or an aftermarket spreader bar.
2) Make sure the water pump hoses on the crate engine enter and exit the same way they are now.
3) Your existing fuel pump may not supply enough fuel if the new engine is considerably more powerful. EFI systems typically require much higher pressures than naturally aspirated engines. EFI also requires gas tank baffles or secondary fuel canisters to prevent losing prime when the gas in the tank gets low or during hard turns.
4) If you are going to a higher compression engine you may need a more powerful starter.
5) If you have an evap/purge system you may have to block it off if the crate engine doesn't support it.
6) Many intake manifolds are too high for the C3 hood. Make sure the intake manifold is a low profile or you will have to invest in a drop base air filter or change the motor mounts, etc.
7) If you have headers, new accessories may get in the way.
8) Your drive line components can handle a pretty sizable increase in horsepower ... unless you start running with slicks or drag radials. Then you are going to have to invest in a lot of drive line upgrades.
9) Make sure your cam isn't so aggressive as to drop you below around 13 pounds of vacuum. Then other issues start to popup (or not popup in the case of the headlights)
10) Remember where all your existing grounds are attached on your current engine so you can replace them with the new engine.
11) If you have a pre-75 your tach is mechanical and may require an adapter.
12) Your crate engine will need a mechanical fan unless you are planning on converting to electric.
13) I'm not sure if this is an issue but if you have a manual then I am assuming all SBC have a Z bar pilot hole?

That's all I can think of ...

 

Great points!
Yeah the Mark VI big block does NOT have a mount for the Z-bar. I had to convert to Hydro.
#9 is important!

 

Is this the car that's got a new frame now ? Just remember if you get a crate motor from the U.S.A there's the shipping cost as well and you need to clarify with them (supplier) what happens if the motor needs any warranty work during the warranty time (if there is any warranty at all !).

I know Eagle Performance are agents for the GM Performance motor(s), they are local too , Sydney and Melbourne I remember . Prices seem high but remember there's no extra shipping cost on that (they have already put it in their price ) might be worth going local if you want to swap out motors ,then you could possibly trade your old engine in as a core.

Me personally , I wouldn't just dump the original , I would get it tested i.e compression and leak down and see what you have and if reasonable , find a builder who could freshen it up and drop it back in for you.