69 L71 Engine Rebuild
Thread Starter
4th Gear
Joined: Jul 2015
Posts: 4
Likes: 0
69 L71 Engine Rebuild
I would like your advise please.
I have an 427/435 L71 convertible that I need to rebuild the engine. When I purchased the car it had a 68 block in it. The original block cam with it. All the other parts that are in the car are original to the car. I want to rebuild the block so I have an all numbers car.
Would you upgrade or put in new crank and cam shafts, pistons, ect. for better performance. Or would you go with all original parts?
The matching block has been magnafluxed so no problems there. It has been bored.
What would you guys do?
Thank you,
I have an 427/435 L71 convertible that I need to rebuild the engine. When I purchased the car it had a 68 block in it. The original block cam with it. All the other parts that are in the car are original to the car. I want to rebuild the block so I have an all numbers car.
Would you upgrade or put in new crank and cam shafts, pistons, ect. for better performance. Or would you go with all original parts?
The matching block has been magnafluxed so no problems there. It has been bored.
What would you guys do?
Thank you,
Burning Brakes
Joined: Mar 2014
Posts: 904
Likes: 46
From: Crestline CA
The crank should be forged and will be fine. The pistons will need to be changed since you said block has been bored so a nice set of forged pistons will be in order. The cam is actually pretty good but I would upgrade to a roller cam if it were me. You didnt mention the heads but if they are original leave them, if not you could upgrade to nice aluminum set for nice power increase. Other than that and a nice double roller timing gear set the factory stuff is pretty good.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If you want it to appear 'all-original', do as suggested in previous post. If stock crank is in good shape, reuse it. Go to roller cam if you have the funds. {Don't go 'wild' on the cam if you keep the stock heads.} Keep stuff on the outside original. It should be plenty powerful and last for another 30 years (or so).
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
my 68 L71 was upgraded to forged pistons and mechanical roller cam.
it's the IU block so aluminum heads. the only other thing changed is the rods to the 502 7/16 stronger ones.
it dynos at 507hp @ 6100 and a flat torque curve 400+ from idle to 482 @4800
cam is comp cams mech roller 282/292 street performance.
if that helps...
it's the IU block so aluminum heads. the only other thing changed is the rods to the 502 7/16 stronger ones.
it dynos at 507hp @ 6100 and a flat torque curve 400+ from idle to 482 @4800
cam is comp cams mech roller 282/292 street performance.
if that helps...
Drifting
Joined: Mar 1999
Posts: 1,381
Likes: 15
From: Lusby MD
No problems with roller lifter clearance with the factory low-rise tri-power intake?
my 68 L71 was upgraded to forged pistons and mechanical roller cam.
it's the IU block so aluminum heads. the only other thing changed is the rods to the 502 7/16 stronger ones.
it dynos at 507hp @ 6100 and a flat torque curve 400+ from idle to 482 @4800
cam is comp cams mech roller 282/292 street performance.
if that helps...
it's the IU block so aluminum heads. the only other thing changed is the rods to the 502 7/16 stronger ones.
it dynos at 507hp @ 6100 and a flat torque curve 400+ from idle to 482 @4800
cam is comp cams mech roller 282/292 street performance.
if that helps...
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
make it appear stock on the outside, put some new HP inside.
I would use the original block for sure.(do not let them deck/remove your block numbers)
mild Cam, or your vacuum won't operate all the accessories ~ Wipers/Heat/ACs. good luck
I would use the original block for sure.(do not let them deck/remove your block numbers)
mild Cam, or your vacuum won't operate all the accessories ~ Wipers/Heat/ACs. good luck
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Drifting
Joined: Mar 1999
Posts: 1,381
Likes: 15
From: Lusby MD
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
Interesting, have not seen that...perhaps that's why my Uncle used mechanical rollers instead of hydraulic when he had it done (he's no longer addicted to oxygen, so I can't ask him) How much taller are hydraulic rollers than mechanical? I would assume they are the same height to use same pushrods. may have to hit my BB engine build books and see if they reference any possible combinations that give interference. I have never seen it on small blocks though.
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
I would like your advise please.
I have an 427/435 L71 convertible that I need to rebuild the engine. When I purchased the car it had a 68 block in it. The original block cam with it. All the other parts that are in the car are original to the car. I want to rebuild the block so I have an all numbers car.
Would you upgrade or put in new crank and cam shafts, pistons, ect. for better performance. Or would you go with all original parts?
The matching block has been magnafluxed so no problems there. It has been bored.
What would you guys do?
Thank you,
I have an 427/435 L71 convertible that I need to rebuild the engine. When I purchased the car it had a 68 block in it. The original block cam with it. All the other parts that are in the car are original to the car. I want to rebuild the block so I have an all numbers car.
Would you upgrade or put in new crank and cam shafts, pistons, ect. for better performance. Or would you go with all original parts?
The matching block has been magnafluxed so no problems there. It has been bored.
What would you guys do?
Thank you,
It all depends on what your goal is and how often you intend to drive it.