cor66vette

What do you do when you purchase a car and was told at time of purchase that the motor is a 327/350 only to find out afterwards that the motor is a 327/300 "re-built to 350 specs"? ( I guess more homework should have been done by me). I am finding some items, such as radiator hoses, etc. with 327/300hp part numbers and others, like intake manifold,etc. with 327/350 #s. My question is actually whether I should lean towards future restoration parts for 327/300 or 327/350 ? :_dupe: :nopity

Vetterodder

I think it will depend on what your goals are. If it was originally a 300hp car and you want it to look correct it won't be that difficult to change the intake and valve covers back. If you aren't looking to have the car judged on originality and you prefer it as a 350hp car for you own enjoyment, use 350hp parts. Is this the original engine with it's original stamping?

As far as the car being represented as a 350hp when it wasn't, the seller was either ignorant and/or dishonest. Yours is a good example of why it's important to know the differences before you buy or take someone with you that does.

62fuelie

Other than camshaft and intake manifold, there isn't a whole lot of difference in the two engines. The compression on the 350 was higher originally, but once rebuilt, most folks lower the compression a tad to compensate for today's crummy gas. Only real visable difference is the aluminum intake and aluminum valve covers.

Make it whatever you like and enjoy it.

MikeM

In addition to the above referenced differences, the 350 used the water pump with the by-pass hose in the intake. The carb was a Holley instead of AFB and internally, the intake and exhaust valves were bigger. Still to mention, the 8" harmonic balance instead of the smaller piece and I believe the right hand exhaust manifold on the 350 did not have the choke tube installed as did the 300. I mention this only because I am unclear as to what you mean about purchasing replacement parts. If you have to replace one of the parts I mentioned, you will have to know what it really is. If you are talking about making a permenent change to one engine or the other, I agree, make it what you want.

Mike :)


[Modified by MikeM, 10:59 PM 6/29/2003]

396 RAT

Was the car a 300 or a 350 when new?

Tony67

when you say the car was sold as having a 350hp
did you look in eng. pad and checked the code suffix
to see if it was stamped for a 350hp?

The suffix for a 350hp is, HD. MT,AR; HP. MT,PS,AC; HT. MT.

You can get a copy of these # at Action Corvette.

Hope this helps

Tony :chevy

62fuelie

Thre were more external differences in the 65 than in later years. The 67's both used a Holley, not sure about 66's.

Paul L

Mike,
I am new to C2s so please bear with me. Here is a pic of base #3872783 and L79 #3890490 intakes (basement inventory). I plan to put the L79 version on my 327/300 shortly. I do not see a bypass on the L79 intake. The heater hose snouts look identical. As I have ordered what I thought were all the parts needed for the conversion, I hope that I have not missed a few:
-longer choke rod
-intake vacuum fitting
-crankcase vent tube and hose kit
-fuel line-pump to carb

Also it is my understanding that the Holley #4160 was the carb for both engine options. I am speaking of 1966-67.






[Modified by paul79, 8:45 PM 6/29/2003]


[Modified by paul79, 8:49 PM 6/29/2003]

396 RAT

"My question is actually whether I should lean towards future restoration parts for 327/300 or 327/350 ? "

What was the car origionally? Theres your answer (as you sound like you want it correct as it left the factory. L79 or not.
In 66 they all used Holley's.
Whats your tach redline at?
Not 100%, but its a start.
Do you have any info on your car?

62fuelie

In the picture, it looks a lot like a plug underneath the water outlet. That would be where the fitting for the by-pass hose attaches.

MikeM

Paul:

Unless my memory has failed (again) you should have a 90 degree fitting coming off the top of your water pump (your picture) go about one inch to the left and one inch back and hit the manifold nipple, right under the thermostat housing. Your water pump looks right. I can't tell about the shot of your manifold on my screen.

The 4160 is right, I don't know the model number off the top of my head. There were a lot of different styles of 4160's

Mike

Paul L

Thanks Mike. This little project is getting complicated as they tend to do! The aluminum intake has a blind plug in what I believe is the hole you are referring to. With the waterpump it seems that I must find a fitting to substitute for that large plug on top.

If anyone has a pic of the 327/350 setup it would be greatly appreciated. Another option MIGHT be to run without the bypass. But is that viable/will it work?

(I checked Dr. Rebuild's catalogue and the 300 and 350 pumps have different parts numbers. So this conversion is getting expensive!)






[Modified by paul79, 7:26 AM 6/30/2003]

65tripleblack

Mike:

You should see a plug just below the t-stat housing. Remove the plug and purchase the nipple for the water pump external bypass hose. The manifold originally had the nipple (straight) installed. When someone replaces the pump, they buy the cheaper type with internal bypass only, remove the nipple, and plug the hole in the intake.

Joe

65tripleblack

Paul:
In addition to the nipple for the intake, you also need the straight nipple for the top of the pump, and the 90* bypass hose, all of which are available from most Corvette parts houses (I like to use L.I. Corvette Supply)
All water pumps have an internal, as well as an external bypass, so it will "work" either way (as you have it on your engine now with the bypass port plugged. The external bypass provides more flow for faster and more even engine warmup.

Joe

TheOman

I have been following this for a while and I need to ask a question. How many entusiasts does it take to swap an intake manifold? WOW! We are not talking about a heart transplant here. A little reverse engineering in front of the TV with a parts catalog and a beer should be all that is needed to come up with the right parts. Look at the 300 and 350 HP parts in question: anywhere there is a different part number there are different parts required for 300 and 350 HP engines. All ya gotta do is decide how much you want to spend for the visual effect of the 350 HP engine and how important correct internal "guts" are to you.

The 300 HP balancer is different from a 350 HP, the valve covers are different, I think the pipe up to the airfilter base is different, the carbs are both Holley for the the 300 and 350 HP engines (after 65..in 65 there were Carter AFB's on the 300 hp cars). They are a different Holley list numbers but physically they will intechange. The fuel lines physically interchange also. Tthere might be an oh so slight difference in shape due to added height of the aluminum manifold but a little discrete bending should get ya there. After all a lot of these repop parts require a little massage anyway.

I had a new L-79 in 67 and I gotta say that altough the internals are quite similar the overall 350 HP package is alot snappier / crisper / cleaner reving than the 300. I never had trouble dispatching the 300 HP cars even when the drive trains were the same. The L-79 cam is a masterpiece combination of flexibiltiy and power and it likes the 11:00 compression, the 300 HP cam is a dud by any measure and the 1/2 point compression difference only highlights the margin between the two cams from a perf. point of view. The 300 engine is outta steam by about 5000 RPM under the best of conditions while the L-79 is still pulling at 6000. When guys I knew with with 300 HP engines reloaded with the 151 cams and skipped the rest of the L-79 specific stuff the lack of the rest of the pieces showed. Those parts added something extra to the performance of the stock L-79. In summary the added compression, the intake manifold and the added valve size (minor as it is) rounds out the L-79 package very well. I have seen and heard the "built to L-79 specs" stuff and all to oftern it means a carb, valve covers and an intake. Having owned both engines that "Built to...." usually turns out to be just another one of the fantasies of the Corvette Hobby. They are not the same if all the parts are all not the same. I currently own a 300 HP car and compared to a 350 HP car ...well there ain't any comparison for my money.


[Modified by TheOman, 9:59 AM 6/30/2003]

Paul L

I appreciate your comments very much! What you are describing is very similar to the differences between late 1970s L-48 and L-82 engines, with which I am very familiar having owned my L-82 for 17 years. With the type of mild driving I do the L79 visuals is the objective. The 300hp internals for my 1967 are fine for that purpose.

That vehicle was purchased just four weeks ago and I am not familiar with the various nuances in the engine configurations. But I have learned a lot from this thread already and will no doubt learn a great deal more in the C2 Forum as time progresses! Thanks again.

JohnZ

Paragon, LICS, the Doc, etc. have the bypass hose, clamps, and fittings you need - the intake and water pump are fine as is. Both 300's and 350's used exactly the same carb - Holley 4160, List #3367, P/N 3884505. :thumbs:


[Modified by JohnZ, 12:08 PM 6/30/2003]

bcwaller

Here's Picture (from above) of the bypass water pump fitting and hose. Conveniently, the intake has been removed. :D

Paul L

That is very much appreciated! So it is a 90 degree metal fitting on the pump going to a 90 degree hose going to the intake snout. Exactly what I was looking for. And the catalogues do not show clearly! Many thanks!

bcwaller

No problem. I started documenting as much as possible once I had the digital camera. No garage should be without one!

Here's the view from the other side of the car:



If you really need the parts, I don't think I'll be re-using the adapter and 90 degree fitting, but I would think you could find them, maybe even at a hardware store!


[Modified by bcwaller, 5:11 PM 6/30/2003]