Spent many years and dollars building my 1965 425 "Super Rocket ". .030" over pistons, .010 under crank, full forged internals, ARP everything, Edelbrock intake and 4bbl., .496/.512 cam," roller tipped rockers,competition valve job,etc... After all this and a full day on the dyno it produced only 385 horsepower and 440 lbs/ feet. According to the factory specs I only gained 10-15 horsepower and LOST 100 foot lbs. What happened or where did I go wrong?

 

It's not quite that much. Your 440 number is 30 less than the highest rated 1965 425, which was 470 ft-lbs. And the factory numbers in the 60s - early 70s weren't realistic to begin with.

There are a lot of variables that could come into play to cause your engine to show less torque. Hard to diagnose over the internet.

 

I was expecting the numbers to increase. Virtually every single component was replaced/ upgraded. With the exception of the block, connecting rods, and crank. Original F1 "A" block. "High nickel content "? Transplanted into an originally equipped 455 four speed 1976 Trans Am. I knew a guy back in Duluth Minnesota that had a built 425 in his 1965 442 and he was producing an estimated 550 horsepower and running a 200-250 shot of nitrous. Just disappointed that I actually lost power. Thanks for the response.

 

Maybe the guy in Minnesota can estimate a higher horsepower and torque number. For now, you have actual dyno numbers.

 

Just a guess-low compression engine build with a bad combo of parts?? What is a "competition valve job" consist of?

 

Good points.

Perhaps if you list the parts used we could help.
- Pistons (manufacturer and part number)
- Head specs (which ones, what combustion chamber size)
- Carb make / size
- Distributor and timing specs
- machine work performed (block, heads)

 

I appreciate the feedback. Compression checked at time of build 9.66. Performer dual plane. 4.96/5.12 Engle cam. 112 lsa. Competition Cams valvetrain.+.030 Speed Pro forged pistons. Edelbrock 1406 750cfm carb. Roller tipped rockers. Manley 1pc. forged valves. 1 pc.forged oil restricted push rods, etc... Engine built at GAM Racing in Greeley Colorado. I believe the competition valve job consisted of three angle valve grind, port and polish. Line honed. Bored with torque plates. Guess I could have gone with a more aggressive cam. Don't know the math for calculating horsepower but based on my time spent in my friend's 442 I was expecting a little more power. 4,200 pounds. 4.56 gears. 27.5x11 wrinkle wall slicks. Muncie M22 "Rock Crusher ". 12.14@ 114mph on the motor. Low 11's on the bottle. Tire incinerating power in every gear. Pulled the front wheels a foot off the ground in 1st and 2nd gear. He built the car in the eighties. Pretty impressive even by today's standards. He was my inspiration for choosing to build a 425.

 

I never knew a factory stock 425 to make 540lbft of torque.
You’re giving up 20 with that carb, just sayin. Cam is antiquated too, That’s a 50 year old generic grind. Sorry.
What was the measured comp ratio? Air/fuel on the dyno? Timing? Did you verify how the intake fit?
Let’s start there.

 

Forgive me for getting any of this wrong but the engine was built almost 10 years ago. Hoping to have it going by the end of June. Heads were resurfaced. 234 degrees cam duration? 34 degrees advance installed straight up. 22 cc dish on the Speed Pro forged pistons. 2.07/1.71 Manley 1pc forged valves. Heads flowed at 240-260 cfm? Full MSD ignition. I'd have to dig up the paperwork to get the exact numbers on everything.

 

Cam should be 224/234@.050 on a 112. I figure your compression at less than 9.0:1. With that cam it’s no wonder it’s a pig.
That cam is slow and lazy, especially with the marginal compression. In a nutshell, your combination is bad.

 

How aggressive could i go with the cam? Money permitting I'd like to upgrade to a hydraulic full roller set up. Edelbrock heads. EFI. And Tremec TKO 600.

 

Compression was verified at 9.66:1. Cam was rated? at 1,200-6,000 rpm. Can't go much higher on the compression and still run on pump gas. They recommended at least 91 octane and 93 if possible. Premium in Colorado is 91. In hindsight a lot of the recommendations from Mondello Performance probably weren't ideal. I started accumulating parts for this engine 25 years ago. Thing's have obviously progressed a lot in a quarter of a century. One of the many downsides of being poor. Didn't have the funds to write a check for 10 grand.

 

How aggressive could i go with the cam? Money permitting I'd like to upgrade to a hydraulic full roller set up. Edelbrock heads. EFI. And Tremec TKO 600.

 

At the time of accumulating the parts for my build the selection of parts for Oldsmobiles was EXTREMELY limited. Early 1990's. Wasn't my goal to build a strip car. Just a strong and reliable weekend car. Unless you have hundreds of thousands to build a 7 second street legal car there's little to be gained by dumping a boat load of money into a classic car.

 

22cc pistons, most likely .030 in the hole, and typical bb heads (80cc) gives you about 8.75:1, not 9.6. Who measured it?
Replace the Speed pros with the New Mahle pistons and ill bet you gain 30hp right there. Again your base combination seems to be wrong.

 

Thanks Mark for your great input!!

 

Like I said i purhased a majority of these parts back in the early 90's. So my memory may be a little foggy on the exact specifications. Pistons were 18-22cc dish. My original A heads were found to be basically shattered after magnafluxing. Put me in a bind. Owner of the machine shop had a set of C heads in stock and I bought those. Wouldn't milling the heads and gasket thicknesses have a direct effect on the compression ratio? The shop that built my engine builds a lot of high end engines so I am assuming they didn't just pull 9.66:1 out of thin air. I realize my build is not ideal by today's standards. I hope to correct some of the shortcomings next year. Appreciate all the feedback. Thanks, Tom@ 4milefirebirds.

 

1965 A block =45° camshaft, factory had thin steel head gaskets. Decked C heads with fat Fel-Pro head gaskets = pretty much stock compression ratio but 432 cu in. Your short block is basically a stock engine+7 cu.in's. Is your camshaft a 45°, was it dialed in with a degree wheel? I believe you mentioned "straight up". Carburetor not the best choice. At what rpm's was peak hp/peak torque?
A heads were good flowing factory head but had different rockers. Your reworked C heads may flow a bit more than the A's.
I remember a 1965 425 stock build-up article, it was a large valved A heads.. Probably had 7 dyno pulls, couple cam changes/ intake changes, even re-ringed it.. They finally wringed 402 hp out of it with 2 four barrels. If I recall the factory camshaft made the most torque till around 3,000 rpm's.

 

Crank shaft was mmachined -.010 for a total of 434 cubic inches. The engine started as a Super Rocket. Ultra High Compression. U imagine that with today's crappy gas it would be pinging like crazy if the stock compression was retained. I'm getting the impression that my engine sucks. Any suggestions on best bang for the buck on what would be my course of action.?

 

Since i lack the knowledge to completely rebuild an engine I had it professionally built. 8 hour dyno tune/break in. I have the dyno sheet. But not with me. Peak horsepower was 386 and change. Timed with degree wheel. Pretty sure that's mandatory. Spent $4,000 on machine work ,assembly, and dyno time. Torque was 444? and change. Approximately 300 plus foot pounds @ idle. It was gaining power on every single pull. Line honed and bored with torque plates. It may produce more once i get it on the road. I was hoping that after seeing 455's producing 450-550 horsepower that my engine would have produced no less than 400. The 425 is basically the same engine with a slightly shorter stroke. If you or anybody else out there has any suggestions of how to achieve or exceed 400 plus without spending thousands of dollars I'm open to suggestions. Thanks for the feedback.

 

 

And don't assume they know how to figure comp ratio without book specs, and those are normally wrong anyway. You'd be surprised how many shops don't have a clue.

 

Not that one could bet their life on the factory numbers, I think the 1965 425 engine from say a 98 model was 365 hp.Your engine vs stock 365 engine has a small plus in the cubic inches, a wash on the compression, probably a small plus on head flow, a small plus on the intake manifold, I'm calling a wash on the carb, that's one area I'd be looking at. Now back to camshaft. Did you get it from Mondello? Is this a JM 20-22? I thought that camshaft was LSA 110? I'm curious to see what camshaft Mark will suggest for an improvement. Jmo but I don't see you changing pistons but a camshaft change is doable. If not then carburetor and timing are areas that "may" improve your numbers. 386 true hp is a decent number for a street car. Btw, seeing as I believe your block is a 45 degree block, all C heads are from 39 degree camshaft angle. Some say when mixing and matching 39° VS 45° heads and blocks that the pushrods "may" rub the lower head pushrod holes. You may want to pop a valve cover off and check your pushrods in that area for shiny areas on the pushrods. Your probably ok but? As I said, I'm looking forward to seeing any camshaft suggestions. As the song goes, "sometimes you just got to love the one your with." Good luck.

 

You may be right on the cam, it could be a JM 20-22. My bad.
But remember those hp ratings were done using waaay better fuel than what we have today.
And as far as a cam recommendation goes, I wouldn’t change anything yet, until he verifies his real world comp ratio.

 

Thanks for the response. When I puchased the jm20-22 cam that was the one Mondello had initially recommended for my parts combination. I also based my decisions on what was available at that time. Back in 1995 there wasn't much available for Oldsmobiles. I thought that once you got too far beyond .500 lift you would start running into problems.? When I finally got close to having all the parts accumulated for the build i called Mondello to place another order. During that conversation i mentioned my cam. The tech sarcastically said "are you building an engine for a motor home". Ouch. I've got over a thousand dollars in parts that ended up not being compatible with my engine. Also received damaged parts,used parts, and rusty parts. Not at all impressed with Mondello's customer service or tech support. Any way the engine was professionally built and is now currently installed in my 1976 (originally) 455 four speed Trans Am. Money was an issue. That is why it took almost 20 years to get all the necessary parts. If all goes well I'd like to upgrade to a full hydraulic roller set up, EFI, and a Tremec TKO 600 next year. It took a LOT of money to get this engine built. Now I know why everybody puts a small block Chevy in EVERYTHING. Model A,lawn mower, blender etc... Lol. Still haven't learned my lesson though. I've also got a 1977 Formula.I'm going to build the 1972 Pontiac 350 that was in my Trans Am when I bought it for that car.

 

Which "Mondello" did you contact ? Was it in Pasa Robles, CA ?

 

Yes. The one in California. Didn't realize there was more than one Mondello. I could go on about all the problems I've had with them. Couple examples. Received an alternator. $200.Rattling on arrival. Was told by Lynn that it would "magnetize" and stop rattling. At the time of installation pulled the case apart and found the brushes were shattered into tiny pieces. By the time I figured that out their 30 day warranty had passed. Reconditioned accessory brackets $300. Not compatible with my engine. Approximately $1000 worth of ARP hardware arrived in one big bag.Nothing sorted or labeled. Timing gear set. $200. Scratched, gouged, rusty. Previously installed/ used.? Most recently $600 spent on custom billet aluminum accessory brackets. Guaranteed to fit. Shocking. They don't. Power steering pulley is way out of alignment. Realized that it can be aligned but may have to search for a unique bolt that may or may not exist somewhere on Earth. Competition cams adjustable valvetrain. $300 pus. Came with mounting hardware that was not compatible. I worked my butt off for years to be able to afford all the parts i bought for this engine. Hope this information gets out there.

 

Unfortunately you’re just one of many. Can’t believe the guy is still in business.

 

Heard things took a turn for the worse when Joe "Dr. Olds" Mondello passed. Wish he could return and pimp slap the people running the company now.lol.

 

Bernard Mondello (Joe's son) has a company in CORONA, CA. Bernard is also a member on this site. There is Joe's widow in Tennesee with a company/school. You managed to pick a company that "uses" the Mondello name. Unfortunately, you paid your money to someone that has been "questionable" for years. All you can do now is salvage what you can and make good purchases for here on out. Cutlassefi is a good source for the correct parts and information.
......Just my two cents worth.

 

Good to know that there is someone else out there. Do they offer any performance parts for the 425/400/455?

 

385 true hp is a lot for a street car, plenty of torque. Just deduct all the bells and whistles amount that you didn't use and the cost seems more reasonable. Are you running tube headers or factory headers? Seeing it's in the car, carburetor and timing/tuning is the only option left for finding a few more ponies. JMO, don't waste your time building a 350 Pontiac, put a 403 Oldsmobile in it. So easy to make hp and torque.

 

One more thing, I don't want to be a negative nellie but I would cut the oil filter open to inspect them for metal at least for the first few oil changes. Pushrods rubbing, camshaft wiping, etc.
https://www.summitracing.com/parts/s...8aAuBlEALw_wcB

 

Happy to help any way I can. My reputation speaks for itself. Overall you’ll get lots of good information here as well.

 

Appreciate the positive comment. I'm running Headman Elite full length headers. X pipe. 2.5 inch dual exhaust. Engine builder said it would be reasonably safe to run a 50- 75 shot of nitrous. All engine internals are forged. Every single bolt that could be upgraded to a stud was. Every single nut and bolt upgraded to ARP. I've been a little surprised about all the negative comments on the Edelbrock carb and my build in general. Aftermarket support for Oldsmobiles was pretty weak back in the early to mid 90's when I puchased most of these parts. Regarding the Pontiac 350. It was in my 76 TA when I bought it. Runs pretty good. Drove it 200 miles before I pulled it. Playing it safe and cheap on this build. Reseal,cam, 625 Demon, dual exhaust. Got the TA for $1200. When I selected the parts for the 425 my goal was to have a strong reasonably reliable weekend toy. Considering that i upgraded every single component I was surprised by an increase of only 15- 20 horsepower over bone stock 425 4bbl.

 

I've already got gallons of oil ready to go for the first few oil changes. And quarts of zddp additive. And gallons of high zinc oil. Running a Mondello supplied Moroso 7 quart street/ strip oil pan with fitted crank scraper. Hoping to have the TA on the road by the end of June. My 39 year wait my finally be over. Bought the 425 in my hometown Duluth, Minnesota back in the summer of 1990 for $250. Brought it to Colorado with me when I moved out here in 1993.

 

What's your website? Tried to look for you and only came across universal efi conversion kits from various companies.

 

It’s in its infant stages, just haven’t had time but it’s newoldsperformance.com

Thanks.
Mark

 

What parts and or services will you be providing? I will be making some upgrades next year. Money permitting. Thanks, Tom@ 4milefirebirds.

 

Engine specific multiport EFI. Small block Stroker cranks, more parts from Mahle Motorsports and others.