RonCL55

Hi all, I hope you can give me your thoughts on my crate motor choice.

I bought a fully restored 65 327/300 convertible. As you can see from the picture it is in great shape. I have decided to put the numbers matching engine and powerglide in a box and update the running gear. However, I only want to go so far. I really like the car and I want it as a cruiser, not a street racer. I don’t intend to change the suspension or wheels because the car is rock solid at 80 MPH, rides decently and handles adequately in the corners as a cruiser. So this is strictly a running gear swap.

For the transmission I have decided to go with a 700R4 from Bowtie Overdrives. That will give me a significantly lower first gear, smoother shifting and a higher top gear. All good. With whatever engine I go with I have decided to go with a Holley Sniper fuel injection and electronic ignition for reliability. I am also going with a low rise dual plane intake manifold (to stay with the original hood), aluminum heads and hydraulic roller cam. No headers or side exhaust, staying with the present exhaust system.

I have read tons of threads on this site and I thank all of you because that has allowed me to get to this point in the decision making process.

So that leaves the engine choices. With my decision to stay with the current suspension and wheels that probably tops me out at the low 400s for useful HP and torque. I also want to stay with the “old school” look when you pop the hood. Based on what I have found so far that probably means going with a 350 or a 383 crate motor. At the moment I am probably leaning towards a 350 for drivability since every YouTube video that I have seen of a 383 shows that it has kind of a lopey cam which causes a certain harshness when idling. I want a smooth cruiser not a street racer (though since I am upgrading I also want to have the maximum power that the present suspension set up can handle).

I have also been looking at crate motors either from GM Performance or BluePrint, likely leaning a little to BluePrint because you get more for your $ and the remanufactured engines don’t worry me that much since I am driving an old car and they do come with a warranty.

So here is what I am looking at right now:

350

https://www.chevrolet.com/performanc...sp350-385-base

https://blueprintengines.com/product...ock-bp35513ct1(this is a bored out 355 but has comparable power to the GM)

383

https://www.chevrolet.com/performanc...s/sp383-deluxe

https://blueprintengines.com/product...ock-bp38313ct1

Does anybody have any experience with these engines, thoughts on what I said or other recommendations? I am ultimately looking for a smooth performing cruiser with as much HP and torque as my present suspension can handle.

kellsdad

I'll make a general comment and use your first engine choice to illustrate. .... Any time you change from the original equipment you are likely to introduce a series of unexpected changes. For example the Chevy Performance 350-385 uses "Fast Burn" heads and a different intake manifold than original. These two things will raise the height of the carburetor and make it challenging to fit an air cleaner with sufficient air flow. These heads also have a different exhaust port shape than original and will not produce the advertised power with the original exhaust manifold. And this engine has valve covers equipped for PCV system. It is challenging to make them look like an original engine. .... So you are on the right track looking for advice. But you may find your challenges reduced if you look for an engine based on the original architecture and components.

Nowhere Man

Keep the original 327/300 in the car and just add a 200R4 and enjoy.

CorvetteMikeB

"Holley Sniper fuel injection and electronic ignition for reliability."



But go with an electronic 4L60E automatic transmission with overdrive. Holley has a PCU that will run the 4L60E automatic transmission, EFI fuel injection and Holley electric fuel pump, You will also need a Holley C2 Corvette EFI fuel tank with the built in Holley electric fuel pump. Would NOT recommend BowTie Overdrive Transmissions. Would recommend Monster transmissions, stronger, better built, all new internal parts and a much better warranty.
Would recommend Blueprint engines as planned.

BLUE1972

The 383 with the overdrive is better as there is more torque in the engine. Go with a roller cam if you can - less issues and no problem oil changes.

To each his own , but an Edelbrock carb works well and will give many years of trouble free reliable operation for 1/3 the cost.


We got a 383 Blueprint with a Edelbrock Carb for my friend, had it set up on a dyno and it's been trouble free for 6 years. No fuel tank or line change .

Robert61

I would go with a GM!

GTOguy

I agree, 100%. Car is waaay too nice to plunder. An overdrive automatic will enhance the performance of the car greatly, and it will still be mostly correct, and a whole lot more desirable. A 327/300 is a great engine---capable and reliable. Getting rid of the PG with the 1.76 low gear and installing a 200R4 or similar will make the car feel like it picked up 100 HP.

vjjack04

Not cheap, but I would consider this one (search at Summit Racing)...

RonCL55

Thanks all, some very interesting comments. To be clear, I am not thinking of staying with the existing engine. That is going in a box. I really want as modern of an engine as I can get (for performance, reliability and fuel economy features) as long as (1) I end up with something that essentially plugs in without material changes to the car—I know about what I need to do for fuel injection and that is ok, and (2) something that looks somewhat original when you pop the hood.

Right now I am leaning to the 350 as it seems to come closest to my goals. For pure HP and torque I would prefer the 383 but the cam lope is a turn off and I would rather go for less power and a smoother running engine.

So my total sweet spot is a small block producing in the area of 400 HP and FT LBS with as a modern an architecture as possible but still totally drop into the car other than the need to address FI. Anybody with some additional thoughts on this? Happy for people also to tell me any of my assumptions are wrong (such as there is a smooth running 383 with no cam lope and in the HP range I am looking for—would love that, or that the SP350 has a lot of cam lope—that would be bad!).

Drothgeb

I went 383, only used a slightly smaller roller cam than most (225/225 .560). A little less lope, and has tons of low rpm torque. Looks just like the 327/300 that came out.

RonCL55

In terms of the intake manifold and hood clearance, I understand both the 350 and the 383 will fit under my small block hood if I use a Weiand dual plane low rise manifold and I can use a drop down air cleaner as well, if necessary. I also realize that using the dual plane intake manifold and original exhaust will reduce the HP and torque, so I look at the numbers of all these engines merely for comparison purposes.

In terms of the PCV valve, take a look at this thread (item 54). They came up with old school finned valve covers with a PCV valve. Love the lock and I am going to try that myself. I am not trying to look exactly like the original when I say old school, just generally when you pop the hood it has the look and feel of the original.

https://www.corvetteforum.com/forums...with-pics.html

Vette5311

https://www.speedwaymotors.com/BlueP...HP,293711.html
https://www.ebay.com/itm/ATK-SBC-350...e/283395622326

I have used both of these engines in customer cars with great results. both are legit companies with warrenties on their engines. Both are available through Jegs and Summit with free shipping. The blueprint has Vortec heads which may present a bit of a problem finding an intake for hood clearance. The ATK has aluminum heads with the conventional port bolts but check port size for fit on older style intakes. If you are using a 700 it has a pretty low 1st gear so you really don't need to worry about torque or extra cubic inches.
Good luck with what ever choice you make.

RonCL55

Thanks. I had heard that the ZZ6 (which by the way is not that much more expensive than the SP350 in their base versions) was more complicated and not totally a plug and play as compared to the SP350. So my question would be is the ZZ6 readily installed without a lot of additional electronics and things? What is the benefit of the ZZ6 over the SP 350?

RonCL55

I would love to go with the 4L60E but I heard that it would not fit without modifying the tunnel and cutting the cross member. Is that true? I dont want to touch my body or frame. I have been advised by Bow Tie that they make an adapter that attaches to the existing cross member and they shave the ears on the 700r4 so that it is a direct bolt in and I only need to cut 1.75 inches off of the drive shaft. I will definitely check out Monster, hopefully they make something that fits without any mods.

Thanks

Nowhere Man

Your mis-informed and falling into a black hole. You say you want reliability, fuel mileage and good street performance. The 327-300 is one of the best most reliable engine EVER. it won’t win a lot of street races but it’s like your grandmas sewing machine. If you keep the motor and a carb scares you then a new fuel injection from Holley or others will make it like most new engines. Backed with a overdrive your have everything you want. If this is not enough then you bought the wrong car and should sell now

CorvetteMikeB

If you are going electronic ignition & electronic EFI fuel injection, might just as well go electronic 4L60E automatic transmission with overdrive and have the Holley PCU unit run the whole system. The Bow Tie adapter for the 4L60E is a "Joke" at best. But since you will already have the engine/transmission out, now would be the time for any modifications if needed. I heard there are minor modifications, but you would need to contact a Corvette restoration shop for the
details. I do know all modifications can be done with the body on the frame.


to cut 1.75 inches off of the drive shaft......would require the skills of a qualified machine shop....best to contact a Classic Car Restoration Shop to coordinate this small project of yours. But a good project

BLUE1972

If you want an overdrive automatic Call Silver Sport - than make a no cut kit for most cars.

Their kits include all the parts including a new driveshaft. No Cutting, and they work.
You do not have to give up HP to fit under the hood .

68hemi

You seem to always recommend going to a “restoration shop” which is the last thing most seasoned people here would do. Many do their own work or find an older long time mechanic that grew up working on older carbureted cars that don’t charge restoration shop prices. Nobody that knows anything mechanical cuts and modifies an original drive shaft OR sends a drive shaft to a machine shop for modification. You save it as you do the original engine and trans and have a reputable drive shaft shop build and balance a new drive shaft.

CorvetteMikeB

If you want an overdrive automatic Call Silver Sport - than make a no cut kit for most cars.


Head they were also very good transmission

CorvetteMikeB

I do not think RonCL55 will be doing the work???