I have a friend with a 61 that has a tired late-70s 350. He wants to replace it with a GM crate motor, like a 330hp/350 or a ZZ4. Are there any 61-specific issues we should be aware of, like a special oil pan, limited intake manifold/carb/air cleaner height, HEI distributor firewall clearance, etc? I've installed lots of small blocks in lots of Chevys, but never a Corvette. I haven't even seen the car yet, but thought I'd start here.

Thanks for your help,
Mike

 

All factory small block pans, for whichever engine, including crate engines, will fit the chassis with no clearance problems. You will be limited on intake manifold choice due to hood clearance. The best I could do on my '60 was an Edelbrock Performer. I think some have said they could get a Performer RPM under the stock hood, but I know it won't work (too tall) on mine. An HEI distributor will clear the firewall just fine. Make sure you have the proper drive gear for your camshaft selection.

One thing to be aware of is fuel pump mounting, that is, make sure the replacement engine will accept a stock-type pump, if that is what you want to use. If you use a late-model engine with a one-piece rear seal, you will need the appropriate flywheel/flexplate. These are easy to come by.

The front motor mount bolts between the block and water pump. You will need an extra set of gaskets.

Pretty much a bolt-in; just some minor things that are easy to overcome.

 

Exactly the info I was looking for.

I wonder if a Performer EPS manifold would work? Seems like it may be a little taller than a standard Performer, but not as tall as an RPM. There's a also a new design Weiand Action Plus manifold that would work with the Vortec heads on the 330hp/350.

I also need to make sure the 330hp/350 is drilled for a mech fuel pump. Thanks for bringing that up.

 

I agree and have helped with several of these in C-1's. You can install a 350/383 and use almost all the original 283-327 heads, exhaust, intakes, and only 1 in 1000 will know it is NOT a 283/327.

If you want to use the original intake and script valve covers, have the machine shop bore and thread a 3/4 inch pipe thread in the back of the oil galley to use as a road drafting outlet.

Joe

 

My experience as well!

 

The 330 HP crate engine uses Vortec heads. The Vortec heads have a raised intake mounting surface. I doubt you could get a Vortec/Performer combo under a C1 hood.

If you are going to run traditional SBC heads, Wieand makes an intake similar to the Performer EPS, PN 8120 for a traditional SBC. According to the posted carb pad heights, the Weiand 8120 is a touch lower than the EPS.

I have an 8120 intake I'm considering installing on our 62. It is a good design. Accordng to Doug F. (a Holley EFI Engineer) who posts at Team Chevelle, it is worth 5-7 HP VS a Performer EPS. The intake is a light weight casting, that is cast in China and machined in the US. It is noticeably lighter than an older Performer 2101. If I decide to run it, I will drill a hole near the coil mounting tabs, for a PCV valve and baffled rubber grommet. I will also use it as my oil fill location. Our 62 block has a rear vent already.

 

Mine fit with no problem. Sorry for the ugly pic but it runs and drives fine. Someday I'll get a nice paint job and dress up the engine compartment. This is a 350/330hp. crate motor. I did it in summer of 2000. Make sure you get a low intake manifold. I didn't pay attention to that. Luckily my hood already had an old scoop on it. Good luck.

 

Cut it out!!

 

One more thing I forgot:
Since you are required to space out the water pump due to the motor mount bolting between it and the block, you will need to space out the lower pulley a like amount. You can purchase a spacer (got mine from Corvette Central) that slips onto the crankshaft snout between the timing chain gear and the vibration dampener, or you can use washers between the lower pulley and VD.

 

One other thing is that the ZZ4 comes with a long neck water pump - you will have to change it to a short neck to fit this application.

bret

 

I need to find out for sure, because I am leaning towards recommending that engine with the new Weiand 8121 (low rise) manifold. The ZZ4 uses traditional heads, but costs lots more, and I'm concerned the angled plugs may cause a problem. The 290hp/350 is a joke, IMO, because it retains the basic Goodwrench engine's very low compression, but uses a hotter cam. (A formula for low cylinder pressure.) I would buy the base Goodwrench engine and add a modern cam with early intake valve closing angle before buying the 290.

Anyone here using Vortec heads with a stock hood? Maybe the subject for another post.

 

I put a 383 stroker in my 61. I used an Edelbrock RPM aluminum intake manifold and a Demon double pump carb. A drop based air cleaner base and a low profile filter allows it to fit under the stock hood. I used the stock exhaust manifolds and oil pan. 100 cubic inches sure makes a difference

 

Mike, The pic was borrowed from Edelbrock's site. The 8121 is listed by Weiand as A: 3.375" and B 4.50"

Edelbrock Performer Vortec A: 3.87" B: 5.28"

Edelbrock Performer (Pre-86 SBC) A: 3.50" B: 4.60"

Looking at the A/B heights of the 8121, it looks like you might be correct about the Vortec heads/8121 combo clearing your hood. I had an early (pre-86) Performer intake on a stop-gap 305 engine in our 62. With an aftermarket drop base air cleaner, I could NOT run a 1/4" insulator gasket under the carb and still get the hood closed. This was with new rubber motor mount bisquits.

A GM drop base air cleaner provided more drop than the aftermarket drop base air cleaner, but it hit the throttle rod. Some one suggested to me that I try a curved midyear throttle arm and drop-down throttle rod, in order to clear the GM drop base air cleaner. I was looking at one the other day on a mid year, and it looked like it would work... the benefit being that you could (possibly) run a taller air filter element.

If you pursue the Vortec engines, you may want to consider the Blueprint 350 and 383 engines. They are the suppliers of Year One's 400 HP Vortec crate engines. Several guys in the C3 Performance section are running them and are happy with the results.

 

I have a ZZ4 motor installed in my '61. I used manifold that came with the ZZ4, Edelbrock carb and original type air cleaner and hood clearance is fine. I would recommend installing the traditional side engine mounts so you don't have to hassle with water pump leaks. I have redone the mounts twice due to leaks. A real pain to do as you can probably understand.

I believe some of the major corvette suppliers make the brackets to be welded on the frame. I used an Alan Grove alternator mounting bracket, this might be easier without the engine mount also.

If you have any questions, pm me and I can send you some pictures of the install tonight.

Dave