62 340 rebuild thoughts and advice. PICS!

[William C.]

Re: 62 340 rebuild thoughts and advice. PICS!

Let's start with a basic set of questions, what are your plans for the engine and how much do you intend to drive it (miles per year) I've had my '62 Fuel car on the road for about 10 years now and haven't put 15,ooo miles on it. At that rate, it will last several of my lifetimes before needing another rebuild. The pistons are flatops that are in it, and from the pictures don't look very old. The deck clearance is about normal for a smallblock V8, what compression ratio are you looking to attain, with today's gas??

[Duke W.]

Re: 62 340 rebuild thoughts and advice. PICS!

The left deck looks close to level averaging about .031" clearance and taking into account the compression distance of the installed pistons would be about .035" with OE pistons, so it's about .010" high from nominal.

Using the same logic on the right side the deck is probably level and about .007" high. The #8 reading is anamolous and may be due to out of spec rod length or compression height, not the deck.

Nothwithstanding the #8 anamoly a composition gasket should seal up, and a shim gasket may be okay, too.

Given the #8 discrepency, I recommend you have the machine shop measure that actual deck heights of the bare block and see if you can nail down the discrepency.

Use .031" and .028" averages to do some what-ifs with the CR calculator. JE or other piston suppliers can do a custom forged piston - whatever you like - but they will be more expensive than off-the-shelf. They all use the same forged blank, but also consider the off-the-shelf KB157. They are actually listed as replacement for the OE forged pistons.

I'm not sure about the 60-61 cc spec of the 461X head chambers. Have the heads been shaved? If not they should exhibit broach marks similar to the block. A few years ago a local chapter member showed me the 461X heads off his '63 340 HP engine. I recall they did not appear to have been surfaced and the valves did not appear excessively recessed, but he said the chambers measured much higher than the 60-61 cc spec. I may be wrong, but to the best of my recollection he said about 70 cc. I was left just scatching my head.

Are you going do disassemble/assemble the engine or is the machine shop going to do this task?

[Scott M.]

Re: 62 340 rebuild thoughts and advice. PICS!

Custom pistons are going to set you back close to $800. One option is to use the 2166's and flycut off most of the dome to reduce your compression, or use the KB hyper piston Duke mentions above. Your deck height along with a .028" composition gasket, 2 cc dome, (assuming 61cc head) will get you to your target of 10.5.

[Bill O.]

Re: 62 340 rebuild thoughts and advice. PICS!

I went out and checked my measurements and came up with the same numbers so I am confident in them.

Scott, thanks for the info. I figured it would be a much more expensive way to go. I guess I will just wait and see if it needs bored or not. If not, the decision would be easy.

Bill, I will probably keep the car a long time. I would probably never put more than 2500 miles a year on it, however. I do want to get it right once and for all. I never liked the way this car ran from the first time I drove it. With its present 8.75 to one compression I guess I can see one reason why LOL.

Duke, I had planned to let the builder assemble the engine, and then break it in on his dyno. Thought it would be fun to see some numbers. Thanks again for all the help everyone. I am going to bring it to him tomorrow. Just as a thought, does anyone have a recommendation for an engine guy in Atlanta? I was planning on using Tommy Goza.

Oh and Bill, interesting that our cars are pretty close together. I did see the "X" on the underside of my heads on an end intake runner.

Bill VO

[Steven B.]

Re: 62 340 rebuild thoughts and advice. PICS!

Bill, I used to live outside Alpharetta and used Garry Grimes, Twister Engines, on Tidwell in Alpharetta. I have used builders and machine shops in 3 other states and Garry is excellent. He has done thousands of restoration, modified, vintage race (including Can Am), and race engines, has worked with parts manufacturers and Chevy, even Zora and has an excellent collection of Corvettes, '57 Chevys, and BB Camaros. He has a full staff and his shop does all the work. Garry's Dad and Garry have done a number of national record holders. Garry did my original 2X4 283 for my '57 and also my L-82 modified track and auto-X engines. Garry is religous about doing heads and ignition mapping. He is adamant about saving pad stampings on resto engines and mentioned it to me before I brought it up. Garry also called me so I could go to the shop and watch the break-in and dyno runs. After install he told me to bring them back and he would fine tune in the cars. Not many builders record your tire data, transmission and diff gearing to assure optimal power curves. I am usually hesitant to recommend shops but in this case I have had nothing but positive experiences with Garry. Google Garry Grimes and Twister Engines.

I have the KB pistons and have been very satisfied.

Steve
Texas Chapter

[David B.]

Re: 62 340 rebuild thoughts and advice. PICS!

I'm not sure about the 60-61 cc spec of the 461X head chambers. Have the heads been shaved? If not they should exhibit broach marks similar to the block. A few years ago a local chapter member showed me the 461X heads off his '63 340 HP engine. I recall they did not appear to have been surfaced and the valves did not appear excessively recessed, but he said the chambers measured much higher than the 60-61 cc spec. I may be wrong, but to the best of my recollection he said about 70 cc. I was left just scatching my head.

I acquired a set via Craigslist a few years ago, and a machinist measured them at 62.3 cc. It's possible they'd had prior work, but nothing obvious.

[Bill O.]

Re: 62 340 rebuild thoughts and advice. PICS!

Bill, I used to live outside Alpharetta and used Garry Grimes, Twister Engines, on Tidwell in Alpharetta. I have used builders and machine shops in 3 other states and Garry is excellent. He has done thousands of restoration, modified, vintage race (including Can Am), and race engines, has worked with parts manufacturers and Chevy, even Zora and has an excellent collection of Corvettes, '57 Chevys, and BB Camaros. He has a full staff and his shop does all the work. Garry's Dad and Garry have done a number of national record holders. Garry did my original 2X4 283 for my '57 and also my L-82 modified track and auto-X engines. Garry is religous about doing heads and ignition mapping. He is adamant about saving pad stampings on resto engines and mentioned it to me before I brought it up. Garry also called me so I could go to the shop and watch the break-in and dyno runs. After install he told me to bring them back and he would fine tune in the cars. Not many builders record your tire data, transmission and diff gearing to assure optimal power curves. I am usually hesitant to recommend shops but in this case I have had nothing but positive experiences with Garry. Google Garry Grimes and Twister Engines.

I have the KB pistons and have been very satisfied.

Steve
Texas Chapter

Steve, you are the third person in the last 24 hours who has mentioned Gary Grimes. Maybe I should rethink this and give him a call. Sounds like the right guy from your description. And thanks for the feedback on the pistons. It sounds like they are a good option if I need to to to .040 over.

Duke, I forgot about your question on my heads. I don't think they have been cut as I see the broaching although not quite as clear as on the block.

David, thanks for the info on the chambers. I will post as well when I find out.

Bill

[Duke W.]

Re: 62 340 rebuild thoughts and advice. PICS!

Thanks David for the 461X chamber volume data .

Bill, as long as you are going to do a full head massage - pocket porting, port matching and chamber relieving, and hopefully flow testing, each chamber volume should be measured, so you will have the most accurate data to make the final head gasket selection to achieve the target CR.

Lab dyno testing is expensive and IMO the funds are better off used on head massaging and making all the measurements required to bring the actual CR very close to the NTE value with minimum cylinder to cylinder variation. Any experienced engine shop should be able to assemble a vintage Chevy engine such that there is virtually 100 percent chance that the engine will fire up and run satisfactorily the first time in the car.

On road testing and tuning followed by chassis dyno testing is less expensive and more useful than lab dyno testing. Often lab dyno tests are done with headers and almost always with big exhaust pipes and no mufflers. This approximates SAE gross (except for the headers), but what the engine will do in the car with manifolds and mufflers, especially with a high overlap cam, can be signficantly less than typical empirical conversion factors would indicate. A chassis dyno test tells you much more accurately what the engine actually does in the car by applying just one converstion factor - drivetrain/tire efficiency - to estimate SAE net at the flywheel.

On-road testing allows one to do SOTP optimization of the spark advance map and carburetor calibration, and a hour's worth of chassis dyno time with a well thought out test plan can prove the optimization or show opportunity for more.

Dynojet chassis dynos are common (Type your zip code into their Web site locator and find what's near you.), and operators typically charge $100-150 per hour. I will send you my test guidelines, but whichever course you choose, PLEASE, start some pulls at 1000 revs so the low end torque characterisitcs can be captured. We actually DO operate these engines at less than 3000 to 3500 revs. If fact most of use are probably below that level most of the time, and a properly set up SHP engine regardless of what OE cam is installed should be docile and tractible down to 1000 revs or less. If not, something is wrong with the setup.

Duke

[Timothy B.]

Re: 62 340 rebuild thoughts and advice. PICS!

Bill,

In addition to the good advice given here, consider reusing the original oil pump with it's standard 45psi relief pressure. Any aftermarket pump you buy will more than likely have a higher relief pressure spring. If the original pump is there, a good cleaning and end clearance the gears to the cover is all that's usually needed.

[Scott M.]

Re: 62 340 rebuild thoughts and advice. PICS!

Once you examine and handle a set of Crower rods, you won't use China made stuff in your build. BTW, I also received from input and drunk Duke's purple Kool Aid and installed a LT-1 cam in my pseudo L79 along with a LT-1 intake.

Crower rods and KB forged ICONS (1).jpg

[Duke W.]

Re: 62 340 rebuild thoughts and advice. PICS!

Shame on you, Scott. One might get away with a warning if using the LT-1 cam one time to replace a different OE cam, but an LT-1 intake on a 327 means time in the penalty box.

I hope you get a chassis dyno test. If you did a good job massaging the heads I think the LT-1 intake will get you to 300 SAE corrected RWHP. The best I've seen with the the LT-1 cam, 327 SHP inlet manifold, and OE exhaust manifolds is about 290 while still making at least 80 percent of peak torque at 2000 and easily pulling from 1000 revs in top gear.

Duke

[Steven B.]

Re: 62 340 rebuild thoughts and advice. PICS!

What was the deck clearance acceptable deviation, across a single deck and between the two decks, when originally installed by Chevy?

[Bill O.]

Re: 62 340 rebuild thoughts and advice. PICS!

Well I took the engine up to Tommy Goza today and have a very good feeling after talking to him and touring his shop. It turn out that he is one of two builders in GA that has a CNC block machine and said he will definitely bore off the crank centerline if necessary and will not deck. He is going to measure everything as standard practice. He agreed with everyone here about the rods, and likes the choice of the LT-1 cam. Has done quite a few sets of 461 heads over the years (he is 65 years old) for local racers so he agrees with the bowl work and unshrouding. He did say he wants to go with hardened seats and usually goes to a 2.02 intake but leaves the stock exhaust. I mentioned the water jacket issue and he said it is no problem but we will discuss that one further later. He should have it disassembled and measured up by the middle of next week, and will talk to him again then. Thanks again everyone for the help on this project. I am sure I will have many more questions in the next few weeks.

Bill