New to the first gen camaro scene. I hear there is only 5 produced. How can I determine if it's an authentic Yenko ZL1 427? It has Yenko casted above the water pump diagonally slant left to right. Yenko ZL1 cast on the valve covers. Was there any reproductions of this motor and ways i can tell if it is? I was also wondering what this engine would be worth. It runs great, he's asking a lot for it. Up over 100k. Thanks!

Try www.yenko.net. Lots of info there, and quite a few of the members there own yenko stuff.

Yenko made a few different versions of Alu big block Chevy blocks in the late 70s and 80s. There were a lot more then 5 made. Don Yenko probably blew up more then 5 of them while racing. The cast aluminum Yenko ZL1 valve covers sound like the fake ones sold on ebay. Yenko sold a stamped steel tall valve cover with a Yenko crest also from late 70s to 80s. Yenko ran a high performance parts business out of the old Yenko Chevy Canonsburg building after Yenko Chevy dealership moved to the Rt19 location. The Yenko blocks and high performance parts business came years after the Yenko 427 cars were sold in the 60s.

was there some produced in the early 70s for the 69 ZL1 Camaro?

called the guy and he said they are 3946074 heads if this helps any?

I think the 5 made refer to the early blocks that spell out Y E N K O, later blocks had the Yenko crest. I remember one selling on ebay about a year ago, but can't search that far back.
As mentioned before, there is a whole site dedicated to Yenko that has lots of info.

The ZL1 block was still available from Chevy in the mid 1970s. There is an article on the Greenwood Corvettes where they purchased the last blocks that Chevy had in mid 70s. SCCA rules required the ZL1 block and I guess Chevy did not want to make more so allowed Yenko to market the block. Yenko, Greenwood, and others were still racing the ZL1 blocks into late 70s. Yenko was selling to road racers, drag racers, boat, sprint cars etc, so there were a few different versions of the block made. Yenko also sold large bore Can Am blocks, and no water jacket blocks. Not sure how many blocks Yenko sold but was a lot more then 5 blocks. They pop up on ebay for sale and Last one I saw for sale was asking about 20K but not sure what it really sold for.

Does this help at all?

http://cgi.ebay.com/ebaymotors/YENKO-427-ZL1-ALUMINUM-600HP-CAMARO-NOVA-CHEVELLE-RS-SS_W0QQitemZ330050395144QQihZ014QQcategoryZ140684Q QrdZ1QQcmdZViewItem

Interesting Joe, The block the guy wants to to buy has exactly like the picture on the right with yenko spelled out on the block.
68' Ragtop, I saw earlier this morning, while searching for info on these blocks, another one on ebay. he claims 1 of 5 also. Couldn't tell you, not enough experience around these but according to joe.."myths busted?" of only being 5.

uh yeah that would be the one i found searching this morning? Those valve covers have Yenko ZL1 in a different configuration tho.

I have been collecting Yenko stuff for 20 years and can give you my opinion.
I believe those valve covers were never used or sold by Yenko. I have never seen them in any Yenko ads or pictures. Somebody has been machining those reproduction alu valve covers with Yenko, Motion, Nickey etc logos and selling them on ebay.
As far as the number 5 for block production:
There is not much info available about the Yenko blocks. I have old Yenko ads and magazine articles and I have talked with Yenko employees but have not heard any numbers for how many of each style block was made. When I do research on something, I like to see some evidence or at least know who/where the info is from. I would like to know where that 5 number comes from. My first question would be - Why would someone only cast five blocks? Try contacting ED C at copo connection. He has a lot of info on ZL1s.
http://www.copo.com/

So, did you ever make it over to the Yenko site?

I have a Yenko aluminum 427 with the crest above the timing chain. I had one with the YENKO at an angle to the driver side in the past it was a 4.44 bore. There were more than 5 built no doubt but MUCH less than the GM 052 blocks. I believe there are many more of the angle name YENKO blocks because they always seem to have a larger bore more for BOATS and CAN-AM racing. I dont think they are from the same mold. I am very interested in finding more info on these but after a few years of looking this is all i can come up with.

Joe,
I am not sure where Yenko had the blocks cast... I am sure that it was probably at the Winters Foundry (because I read that the molds were found there in the 90's... and in very good condition because of their limited amount of use... then GM decided to build the New ZL1's).
HOWEVER...
Yenko did have quite a bit of his Aluminum parts cast at the Atlas Foundry in PA. If he did indeed have any blocks cast there, no minimums would have applied. Atlas was a locomotive parts manufacturer and the son of the owner raced Corvettes and was very good friends with Don. Atlas cast the wheels for less than the Torque Thrusts cost... rumor is they used a Torque Thrust for the pattern.

James

I have a 1984 magazine article on a Yenko-Chevy 502 build. The block is the alu Can Am 4.44 bore block with liners and has no Yenko crest or Yenko letters. In the article the builder said he found a used block because "Yenko Speed and Marine" did not have any but said they were going to resume production.
I talked to a guy who had a Yenko block with Yenko crest who said it was the ZL1 type block and have heard the Yenko lettered block is the alu Can Am 4.44 bore block. I don't have enough info to say that all the Yenko crest blocks are the ZL1 type blocks and all the Yenko lettered blocks are the alu Can Am 4.44 bore blocks but this may be true.
We know that Chevy made both and they were not the same casting so when Yenko had his made he could have used the Yenko crest on one block and the Yenko letters on the other blocks.
The block in the article has no Yenko ID so there may have been a run of each block with no Yenko ID.
Just don't have enough info yet to say what was done with the alu Yenko-Chevy blocks.

"woundup" was your Yenko crest block the ZL1 type block with 4.250 bore?

I still have the complete engine. It is standard bore 427. It has the crest above the timing chain. It has a casting number that ends with 053Y. It has the winters foundry logo as well. It looks like a standard bbc. The angle YENKO engine i had seemed to be more heavy duty like a rece and or marine race engine. Either one i have seen more than 5 myself over the years. But many more of the angle yenko blocks.

"woundup" Do you think that all the Yenko crest blocks are ZL1 type 4.250 bore and all the Yenko lettered blocks were Cam Am type 4.440 bore?
I have not seen enough examples of each to say for sure but seems like it could be true.

From what i have seen over the years i would say yes. From what i understand the crest blocks are cast from the zl1 molds and have a 053 casting number (at least mine does). The others seem to be more of a race design block with no cast numbers just a few numbers and letters stamped here and there. THIS IS ONLY MY OPINION. I talked to copo connection (ED) and christiensen in denver and they didnt have any info and as far as i know they were the best chance i had.

There must be some old race car guys out there that know more about the Yenko blocks. They ran the ZL1 block in SCCA road racing Camaro Corvettes and Monzas where the CanAm block was not allowed.
The CanAm BB Chevy motor dominated CamAm racing late 60's to early 70's beating Ferrari, Porsche, and Ford, who all had more expensive exotic engines, until Porsche went insane and built their duel turbo 1100hp 12cyl.
They were used in drag racing, race boats and dirt cars.
Bill Jenkins ran both the ZL1 and CanAm blocks.

heres a funny story I like to tell about when I asked Bill Jenkins about the engines he ran

It’s been a few years but I think this is the way the conversation went….
Jenkins had both the "ZL1" engine and the CanAm engine. That was the first question I asked him and I'll never forget what he said because I was so surprised. Grump said, "the ZL1 block was junk" He said it "moved" too much and wouldn't "seal". He said they made a water heater and pump to run water through the block to keep it at 180 deg all weekend. This was to stop the heat/cool cycle from "moving" the block. It would still lose power after a few runs because the block couldn’t take the high RPMs. The CamAm block is stronger because it has a siamese cyl design meaning water does not pass between the adjoining cyls like it does on a normal block. The CanAm block was not legal for Super Stock but was legal for Pro Stock. The ZL1 block worked ok for the road racing Corvettes where the RPM was not as high.

Grumpy ran a CamAm motor in his 68 Camaro match racer and used that same 68 Camaro with the CanAm set-up to win the first ever Pro Stock race in 1970 beating the Sox and Martin Hemi Cuda.

Cool story. I read the same thing about the ZL1 blocks as being junk and i dont doubt it when you push them hard. Thats why the can-am and real race blocks are built much stronger. I just think they are cool and i wont push mine too hard because they are so hard to come by. Because they are not so strong (junk) is why they are hard to find. 20 years ago i bet you would find them in the scrap metal yard. I used to find iron rec-port heads at the scrap yard all the time, i think i still have a few. Never thought to look in the aluminum pile Bummer.

Yenko, Greenwood and others ran the ZL1 blocks pretty hard but the RPM limit was lower then in drag racing. Yenko/Grossman ran a ZL1 engine in a 69 Camaro at Sebring in 69-70. It did pretty well in 69 but blew-up in 1970.
Greenwood did very well with his Corvettes at many races including long ones like Daytona, Sebring, LeMans.

here is some intersting info from the web site for the new ZL1 block.

quote.......
"Back in the day, some ZL1 aluminum blocks experienced durability, porosity, and cylinder-wall-stability issues. This was not uncommon with old-school aluminum automotive engines cast using tooling basically designed for molding cast iron. Foundries and engineers were still on a learning curve when it came to aluminum, which has different gating and rising characteristics than cast iron. Gating is the process involved in filling the mold to cast the block. Rising describes the process of metal coming out or overflowing the mold, allowing gasses and other impurities to escape. Shrinkage must also be accounted for to allow additional metal to flow back into the mold after gasses and other impurities are removed. Problems with these processes can create porosity near the top of the mold (which on the ZL1 is actually the bottom of the block near the oil-pan area, as the block is poured with the deck facing down).
The original ZL1 blocks (identified by screw-in NPT-thread freeze plugs and iron main-bearing caps with straight bolts) were cast in the late '60s and '70s at Winters foundry (its trademark was the classic snowflake symbol). Running aluminum blocks without ethylene glycol-based coolant or with worn-out coolant exacerbates any porosity tendencies, allowing electrolysis to start eating through pinholes at the bottom of the water jacket until it erodes all the way through to the cylinder liner. Because of the potential porosity problem combined with the age of the original castings, it is strongly recommended that old-style blocks be leak-tested and pressure-checked before use. Note too, that the original liners were much thinner than present production units and tended to move around, resulting in high cylinder leakdown rates.
When Winters decided to get out of the sand-casting business in the late '80s, GM did an inventory check and found the original ZL1 tooling tucked away in a back room, intact and in perfect shape! GM decided to bring the ZL1 block back, but with enhancements. The "new production" ZL1 blocks can be identified by screw-in AN-style water-jacket core plugs sealed by O-rings and billet-steel main-bearing caps with splayed outer bolt-holes.
The new foundry uses much-improved casting and pouring technology, minimizing quality-control and porosity problems. The heat-treating is more consistent, the blocks are more stable with less core-shift, and machining is done on CNC-equipment using 21st century standards and technology. There may still be some visible pepper porosity (little specs of aluminum voids formed by escaping gases) in the oil-pan area, but no leakage has been reported. For professional race use, it is still recommended that the block be seasoned to enhance cylinder-wall stability.
Core wall thickness was increased throughout. The cylinder-head decks are now 0.750 inch thick. Improvements were made in the water jacket, late-model production roller-cam lifter-boss retention provisions were added to the valley, and upgraded cylinder liners were specified. The latest upgrade scheduled for blocks produced in '04 is more support around the cylinder liners and even thicker liners that can be bored to 4.350 inches (blocks are delivered at 4.24 inches). These new, thick liners can be visibly identified by checking the register of the liner in the top of the deck. The original liners had almost 0.100 inch of aluminum between each pair; the new liners almost kiss each other.
According to GM sources, an analysis of the current tooling indicates it should be good for another 300-400 blocks before any more major work is required--about six to eight more years at current sales rates. And don't forget that an aluminum big-block will still give up 10-40 hp to an iron one, though it weighs about half as much."

I have the can am crest version in my 69 RS/SS. Not many around in mint condition. One with the yenko name is on on ebay for 55k buy it now. Theres a guy on this site that said he sold one for 4500. LOL Sounds like someone got the deal of a lifetime.

One with the yenko name is on on ebay for 55k buy it now.

I saw that ebay ad yesterday. Here is the link,

http://cgi.ebay.com/ebaymotors/YENKO-427-ZL1-ALUMINUM-600HP-CAMARO-NOVA-CHEVELLE-RS-SS_W0QQitemZ330055812258QQihZ014QQcategoryZ140684Q QrdZ1QQcmdZViewItem

My finger tried to hit the buy it now but my wallet got in the way. :)


I tried to get the bore diameter from them but they only respond that it’s standard bore. They call it a ZL1 but I am wondering if it is a Can Am 4.440 bore block

"cortezsilver"......Do you have the Yenko crest block or Yenko letter block and what bore dia.?

I have the can am crest version in my 69 RS/SS. Not many around in mint condition. One with the yenko name is on on ebay for 55k buy it now. Theres a guy on this site that said he sold one for 4500. LOL Sounds like someone got the deal of a lifetime.


That would be me who sold one with the crest for $4500, shortblock only. It had a 454 crank and pistons so the only value was in the block. It went to a friend so I was fine with the price.

However, the guy on Ebay is on another planet if he thinks he'll sniff anywhere near $55K for that engine. I hope you don't think an asking price on Ebay in any way determines value! :clonk: There have been many sell at well under half that with all the correct pieces.

Jody

I sold my 69 Camaro with the TRACO GM O-Dash casting number ZL1 for a lot less then the 55K that guys asking for that motor.Sure wish I kept that 1 of 1 TRACO ZL1 427 motor,but its in good hands at Ricks First Generation... Dan

I sold my 69 Camaro with the TRACO GM O-Dash casting number ZL1 for a lot less then the 55K that guys asking for that motor.Sure wish I kept that 1 of 1 TRACO ZL1 427 motor,but its in good hands at Ricks First Generation... Dan

And what a sweet car it is,, looked it over well my last visit up to Ricks.
Frank

A memeber here sent me a PM that brings up a good point that we should go by the block bore center to center dimension not the bore diameter of the Can Am block because they had different bore sleeves. They used a thicker bore sleeve to run the Can Am block at the 430 cu in Pro Stock limit. and maybe for other types of racing that had cu in limit. I don't have the bore center to center dimension in my head but the Cam Am block was larger center to center then the ZL1 block.


Dan, was that ZL1 power Camaro in Rick's display at Carlise GM Nationals? I didn't get a good picture of it but think it is behind this Z/28
Rick's had a great display there with a bunch of cross ram's and porkupine head Z/28s and other cool stuff

Frank,Thanks ! Joe,Yes it was at GM of Carlise show under Ricks First Generation Tent.It was lettered up,said Traco ZL1 on it. Dan