Engine Upgrade...Opinions PLZ?
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
Engine Upgrade...Opinions PLZ?
My 73 currently has a GM 350-250 crate w 72cc heads. I have EBrock 2101 intake, a well tuned Ebrock Q-Jet and Dynomax Headers w/ 2 1/2" exhaust. It runs well enough but quickly runs out of steam at 5000rpm. I don't know for sure how many miles are on the motor, but it is very clean inside, not a bit of grime in the lifter valley or anywhere. The plugs all show clean and consistent burn and wear. It burns no oil (none) and never smokes.
So my question is, could I put a top end upgrade on this engine and expect the bottom end to hold, just based on what it is?
I was thinking some 64cc Vortec heads and a L-46 CAM. I think I could come out <1000.00 on parts. I don't drive the car more than 2000 miles year, if even that. Street/cruise use only. Just looking for a little more kick back in your seat. I'm thinkin I could get +75hp out of this. thoughts?
I know I would have to change intakes, but are the exhaust ports the same on the vortecs? Would my headers fit?
Any other cam that would work well here?
thanks in advance as always
So my question is, could I put a top end upgrade on this engine and expect the bottom end to hold, just based on what it is?
I was thinking some 64cc Vortec heads and a L-46 CAM. I think I could come out <1000.00 on parts. I don't drive the car more than 2000 miles year, if even that. Street/cruise use only. Just looking for a little more kick back in your seat. I'm thinkin I could get +75hp out of this. thoughts?
I know I would have to change intakes, but are the exhaust ports the same on the vortecs? Would my headers fit?
Any other cam that would work well here?
thanks in advance as always
Pro
Joined: Nov 2007
Posts: 741
Likes: 1
From: Woodstock GA
My 73 currently has a GM 350-250 crate w 72cc heads. I have EBrock 2101 intake, a well tuned Ebrock Q-Jet and Dynomax Headers w/ 2 1/2" exhaust. It runs well enough but quickly runs out of steam at 5000rpm. I don't know for sure how many miles are on the motor, but it is very clean inside, not a bit of grime in the lifter valley or anywhere. The plugs all show clean and consistent burn and wear. It burns no oil (none) and never smokes.
So my question is, could I put a top end upgrade on this engine and expect the bottom end to hold, just based on what it is?
I was thinking some 64cc Vortec heads and a L-46 CAM. I think I could come out <1000.00 on parts. I don't drive the car more than 2000 miles year, if even that. Street/cruise use only. Just looking for a little more kick back in your seat. I'm thinkin I could get +75hp out of this. thoughts?
I know I would have to change intakes, but are the exhaust ports the same on the vortecs? Would my headers fit?
Any other cam that would work well here?
thanks in advance as always
So my question is, could I put a top end upgrade on this engine and expect the bottom end to hold, just based on what it is?
I was thinking some 64cc Vortec heads and a L-46 CAM. I think I could come out <1000.00 on parts. I don't drive the car more than 2000 miles year, if even that. Street/cruise use only. Just looking for a little more kick back in your seat. I'm thinkin I could get +75hp out of this. thoughts?
I know I would have to change intakes, but are the exhaust ports the same on the vortecs? Would my headers fit?
Any other cam that would work well here?
thanks in advance as always
Le Mans Master
Joined: Oct 2005
Posts: 9,429
Likes: 44
From: Macon, GA
Your bottom end is a 4-bolt main. It should handle just about anything you throw at it. You're making 8.5:1 compression with those 76cc smog heads and that engine tops out power wise at 4,300RPM. Your current cam is about as wimpy as they come. A top end package (including cam) is exactly what you need. I've seen first hand what a Holley Systemax II top end kit will do an a 350 block and it was pretty amazing. That kit has a pretty big Lunati cam that may be a bit more than what you are wanting, but it will fly.
For the money, the Summit kit below can't be beat. It includes nearly everything you'll need for the swap. You'll definately feel a big difference and still be very streetable.
http://store.summitracing.com/partde...rsview=sku&Ns=
Or if that's too much you can de-tune and save a little with this kit:
http://store.summitracing.com/partde...rsview=sku&Ns=
For the money, the Summit kit below can't be beat. It includes nearly everything you'll need for the swap. You'll definately feel a big difference and still be very streetable.
http://store.summitracing.com/partde...rsview=sku&Ns=
Or if that's too much you can de-tune and save a little with this kit:
http://store.summitracing.com/partde...rsview=sku&Ns=
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
Thanks guy's, I guess my real concern about the bottom end is the risk of blowing out the compression rings or breaking a cast piston with the pressure increase.
I like the summit kits but the price is too steep. If I'm going to do that, I might just go all the way with a full new crate engine. I did some searching on the forum and found a few threads where a set of iron Vortec's were recovered from a late 90's vehicle, and the L-46 cam was used at 4* advance. I will most likely call comp cams and get their opinion as well. In the mean time the search for a good set of heads is on.
I like the summit kits but the price is too steep. If I'm going to do that, I might just go all the way with a full new crate engine. I did some searching on the forum and found a few threads where a set of iron Vortec's were recovered from a late 90's vehicle, and the L-46 cam was used at 4* advance. I will most likely call comp cams and get their opinion as well. In the mean time the search for a good set of heads is on.
