C3 Valuation
Thread Starter
3rd Gear
Joined: Jul 2023
Posts: 3
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C3 Valuation
I have owned since 2/7/1971 a 1970 Corvette roadster with 70,998 miles, 350/350, 4-speed. The car is in above average condition. The engine could use new rings. While the engine is removed, I am contemplating some upgrades like cam, pistons, etc. Any changes will be internal only. Car is totally original with all numbers matching. Will any internal changes diminish the collector value? If so, I will just replace the parts needed. Thank you.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,147
Likes: 4,258
From: US-PNW
In my opinion, internal engine changes will not diminish value unless you go so radical that it affects the reliability of the original block. New roller camshafts and the accompanying valve train is a big modern improvement over the old-school flat contact cams & lifters. The computer design for these has really opened up potential performance without adversely affecting manners. Your factory compression is supposed to be 11:1 with the 350/350 so bumping compression is off the table. Do you have any pinging with your local gas?
Since originality is important to you, make sure you stress multiple times (wouldn't hurt to put it on the machine shop work orders) that the engine stamp pad is not to be touched by anything - not even a Scotch-brite wheel.
Since originality is important to you, make sure you stress multiple times (wouldn't hurt to put it on the machine shop work orders) that the engine stamp pad is not to be touched by anything - not even a Scotch-brite wheel.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,235
Likes: 9,376
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
If you decide to go witch a new roller camshaft, be aware that it will cost a lot of money to do correctly. Cutting corners with cheap lifters will possibly destry you motor or at a minimum double the cost of doing it right the first time...so if you do, buy bushed roller lifters not needle bearing roller lifters. A bushed one is unlikely to fail and needle bearings do fail.
If you stay flat tappet, run good oil with high ZDDP and Zinc and it will not go flat. To aid in them lasting the new lifters with oil holes in the tappet face increase oil on that critical surface. Comp Cams is called an EDM lifter. Others make them too.
I just took apart my 427 for a bad bearing and the flat tappets look like new still. Not a mark on them
https://www.summitracing.com/search/part-type/lifters/product-line/comp-cams-performance-series-edm-solid-lifters
https://hotrodenginetech.com/edm-flat-tappet-lifters-johnson/
If you stay flat tappet, run good oil with high ZDDP and Zinc and it will not go flat. To aid in them lasting the new lifters with oil holes in the tappet face increase oil on that critical surface. Comp Cams is called an EDM lifter. Others make them too.
I just took apart my 427 for a bad bearing and the flat tappets look like new still. Not a mark on them
https://www.summitracing.com/search/part-type/lifters/product-line/comp-cams-performance-series-edm-solid-lifters
https://hotrodenginetech.com/edm-flat-tappet-lifters-johnson/
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
Nice.
As long as your changes don't affect drivability causing quirky conditions, meaning
higher idle, slow vacuum systems, hard start, type stuff, new owner would definitely
appreciate a solid motor.
As long as your changes don't affect drivability causing quirky conditions, meaning
higher idle, slow vacuum systems, hard start, type stuff, new owner would definitely
appreciate a solid motor.
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Burning Brakes
Joined: Mar 2022
Posts: 1,159
Likes: 492
Any changes you make, keep the original rotating parts. I have a 69 4 speed vert with original numbers matching motor/transmission, and I went a safer route. I purchased a 396 stroker from Blueprint this year, dynoed at 507 HP/516 TQ, which is more than plenty.
Cost me a bit over 7K, but these days it's tough to build a reliable and powerful motor yourself for less, and the motor has a good warranty - all new forged components and forged rotating assembly -all with a new cast block. Car is still in the process of full restoration (albeit unplanned), but I plan to have the motor in during the winter. Original motor will go in the crate that that the BPE was shipped in, for prosperity.
Cost me a bit over 7K, but these days it's tough to build a reliable and powerful motor yourself for less, and the motor has a good warranty - all new forged components and forged rotating assembly -all with a new cast block. Car is still in the process of full restoration (albeit unplanned), but I plan to have the motor in during the winter. Original motor will go in the crate that that the BPE was shipped in, for prosperity.