Building another BBC on a budget

[RatPwrd72]

Here's a little backstory on the engine I'm putting together for my '72 truck...

Bought the truck in 1997 with the original 402 and 125,000 showing on the odometer. Figured out real quick it used about a quart of oil every 1,000 miles and had plenty of leaks. I was a junior in high school and had spent most all the bank roll on buying the truck. Replaced the valve cover gaskets, overhauled the Q-Jet and gave it a tune up. Didn't run too bad, but was short lived. After a month or so, I discovered the oil pump pickup had fallen off... You know, 60 psi at the stop sign and went to the bottom off idle.

Pulled the 402 and built a shoestring budget 468. Stock cast crank, stock rods with ARP bolts and cheap cast flattop Pistons. Went with a stock set of 049 heads and an Elgin 204/214 @ .050 cam with a used Performer intake and the original Q-Jet. This combo mustered a best of 14.40 in the 1/4 with 3.07 gears and a stock converter.

Fast forward a few years and I decided to up the performance of the 468. Stuck in a Lunati Brackmaster cam, 236 @ .050, .544 lift and cut the 049 heads for 2.19/1.88 valves I had used from the race truck engine. Swapped an Airgap RPM for the Performer and put a 3310 Holley on it, it went 13.80's without much tuning. I did figure out the fuel pressure fell below 1 psi in high gear, but never ran it again after putting in a fuel cell and Holley Blue pump.

So, here we are after the truck has set another 3 years or so, time for a little more oomph, on a budget of course.






Block is already .060" over, so it'll be getting bored to .070", vatted, line bored and honed. I'm shopping for a rotating assembly now, looking for a 4.250" stroke crank,6.385 h-beam rod and forged piston. Probably go with White Performance or CNC Mororsports for this and pick an 18cc dome piston, which should put me right at 10:1 compression.

Stopped at a local speed shop and picked up a gently used Comp HR288 hydraulic roller (226/234 @ .050", 587/610 lift) and lifter set that had 2 dyno pulls on it for cheap, otherwise I was contemplating going back with a flat tappet for budget reasons.

I'm going to run the 049 heads with the 2.19/1.88 valves for now, Good heads aren't in the budget right now... I dont feel ill be leaving too much on the table with these, Torque is the name of the game and I shouldn't turn this deal any tighter than 5,900 or so before I'm out of cam.

I'm shooting for 525 HP on pump gas with plenty of tire turning torque. If anybody has any suggestions for the rotating assembly, I'm all ears. Ill try to update this as we move along with new parts....

[Hollow65]

Eagle or Callie's make a decent rotating assembly.

[RatPwrd72]

I'm leaning towards a Scat 9000 series crank, we've used several of those in SBC 383 builds. The stock 454 crank here has been beat on quite a bit, I think any of the aftermarket pieces should hold up alright.

[Slammed84]

Building same motor here....

Scat makes a nice steel 4.25 crank that you can use with stock rods. I have one in my garage. I can post pics if you want

[RatPwrd72]

Originally Posted by Slammed84

Building same motor here....

Scat makes a nice steel 4.25 crank that you can use with stock rods. I have one in my garage. I can post pics if you want

Sure thing, I'd like to see it. Is it their 9000 series crank? I wonder if theirs any advantage to running the 6.385 rod over stock?

[Super73]

Just thinking allowed here but maybe look at what the the different rod length does to wrist pin location for pistons and where it puts it in location to the rings.

[RatPwrd72]

From the 383 builds I've done, the 6" rod versus 5.7" rod doesn't equate to any noticeable gain in HP, but is supposed to be easier on parts due to rod load and takes some stress from the piston skirts. Probably the same with the 6.385" in the 496. Either way, the cost is minimal and most all of the "kits" are sold with 6.385".

[bbcmudtruck]

I went with the Forged Scat 496 assembly myself. After tons of research and after talking to numerous engine builders, that's ultimately what I decided on. I also went with the internal balance. The guys over at team chevelle are very helpful and really know their stuff when it comes to building streetable metric ton of power! Here is what I've gathered so far for my new build.

291 block on stock bore
Scat H-beam rods
Scat forged crank
Mahle forged 18cc dome pistons
ARP main studs, rod bolts, head studs as well as an ARP engine bolt kit
049 heads with 2.19/1.88 manly SS extreme duty valves. No port work has been done to the heads yet, as I'm still debating on pulling the trigger on a set of AFR 265cc cnc chambered heads.
Comp Cams Stainless Ultra Magnum rockers
Moroso oil pan with windage tray, baffle and scraper
Billet MSD distributor
Holley billet mechanical fuel pump, 170GPH internally regulated.
ATI internal balance super dampner
Edelbrock rpm air gap
Holley 950hp billet carb

I haven't ordered a cam yet, as I'm still trying to decide whether or not to run the 049 heads or come up with the money for the AFR heads. Either way, I'm going to run a Straub billet hydraulic roller matched to which ever heads I use. I'm going a step further with the lifters and going to have my block machined for the .920 lifters. They are larger and stronger than the stock sized lifters. Plus doing this will allow the machine shop to properly size the lifter bores as well as square them up with the block. Overkill? Yes and no. All three of the big name engine builders I talked to about this build all agreed that it would result in more power and reliability. How much power is unknown, however one builder threw out the 15-20hp number. The extra power is strictly coming from proper alignment of the lifter bores as well as properly matched and sized to the lifters. In short, its relieving a lot of friction. I've been accumulating parts and researching different builders and ideas for a year and half now on what the ultimate 496 combo is. If you'd like any help or information that I've been able to gather, just let me know!

[RatPwrd72]

BBCMudtruck, thanks for the advice. I'm a member over at the Chevelles site too and have a cam in my drag truck that was spec'd by Straub, it's a beast for sure.

I ordered the rotating assembly yesterday from CnC-Motorsports.com. They didn't have exactly what I wanted listed on their site, but were more than happy to build me a kit. Here's the rundown:

Scat 9000 series cast 4.250 stroke crank
Scat 6.385 Pro Comp rods with ARP 8740 bolts
Mahle 18cc Dome Pistons with Mahle rings (.070" over)
ACL Rod & Main bearings
SFI flex plate & Pro Street series balancer.

I'm having them do the balance work (external) and I'll give it all a once over before the assembly starts. The price was right and they seemed eager to put together the parts I wanted. Just need to order a gasket set, oil pump and timing chain set to round out the long block build.

[Hollow65]

Team chevelle has a ton of info about pretty much any engine combo possible. Straub, wolfsplac and vortec pro are always showin off builds and dyno runs and flow numbers. Lots of info there. Straub and his squishy rollers are makin serious power!

[RatPwrd72]

I keep telling myself it's a budget deal and I still need to drive it more than 10 miles at a time, otherwise I'd spring for some Brodix Race-Rite's and a larger hydraulic roller.

[Hollow65]

remember what straub always says, "it's in the combo." I think you will reach your goal of 525.

[RatPwrd72]

Originally Posted by Hollow65

remember what straub always says, "it's in the combo." I think you will reach your goal of 525.

I think so too and have a nice flat torque curve, which is what I need in a 4,000 lb truck on the street. Should make for short lived rear tires.

[Hollow65]

Torque is fun, same with horsepower. Stabbin the throttle at 40 and getting sideways with your wife in the truck, priceless!

[bbcmudtruck]

Right on, your headed in the right direction as far as I can tell. Have you checked your cam specs against what Straub uses for 049 heads? You shouldn't have an issue getting your 525 hp goal in my opinion. From what I've read and seen from those guys on their dyno builds, an iron headed 496 is able to achieve 600 more times than not. I would suggest spending some time on the heads while you have them out and on the bench though. Un-shrouding the chambers and a minor port work seems to pay off big time on those heads.

I'm debating going with a new 540 dart block from CNC Motorsports as well. The cost of bringing my block up to snuff is going to be around a thousand bucks. That only leaves me shy of jumping into a better block by 1200 bucks or so. The only thing I've gathered so far that I wouldn't be able to use are my pistons. Since they are new and a very popular choice, I think I'd be able to get most of my money back. On another note, how did you like your 468 in your truck? It seems to me like that would have been a power house as well. I'm heavily debating on putting one of my 468s together until I get my big motor built.

[ptc]

Straub is a great source of info... listen intently!

If you want to stay with iron heads why not go with the 990 rect ports? they will give you more RPM than the 049s if you go to a bigger cam.

Im running a 496 powerplant in my prop boat that is about 700 hp, the 990 heads, dual quad tunnel ram, port matched, Comp cam mech flat tappet cam, Crane valve train parts, SCAT and Crower rotating assembly. SRP pistons 10.25;1 CR on pump gas.

I get about 6900 rpm out of this engine, its instant on the hit and then runs out well. Thinking about the same build for my pro-street truck build.

[bbcmudtruck]

I can't speak for the op, but for me, I wanted a street motor, not a race motor. I simply didn't want to spin the motor that high. I'm absolutely sure you could gain more hp in the upper RPM range, but that will cost you torque in the most used rpm range. I'm building my motor to peak around 6-6200k. The 049s or the 781s are perfect for that goal. Tons of torque right off idle and will carry it through the entire desired RPM range. For the most part, I see 990s being used in drag cars, where they need the rpms on the big end. For a street driven vehicle that wont see 6k+ rpms regularly, you'd be giving up power where you use it most. The 990s are good heads and absolutely have their place, however for a heavy street bound hotrod, I'd go with the big ovals every time!

[RatPwrd72]

Originally Posted by bbcmudtruck

Right on, your headed in the right direction as far as I can tell. Have you checked your cam specs against what Straub uses for 049 heads? You shouldn't have an issue getting your 525 hp goal in my opinion. From what I've read and seen from those guys on their dyno builds, an iron headed 496 is able to achieve 600 more times than not. I would suggest spending some time on the heads while you have them out and on the bench though. Un-shrouding the chambers and a minor port work seems to pay off big time on those heads.

I'm debating going with a new 540 dart block from CNC Motorsports as well. The cost of bringing my block up to snuff is going to be around a thousand bucks. That only leaves me shy of jumping into a better block by 1200 bucks or so. The only thing I've gathered so far that I wouldn't be able to use are my pistons. Since they are new and a very popular choice, I think I'd be able to get most of my money back. On another note, how did you like your 468 in your truck? It seems to me like that would have been a power house as well. I'm heavily debating on putting one of my 468s together until I get my big motor built.

My 049's already have been cut for 2.19/1.88 valves and had minor bowl work done. Compared to what Straub recommends for a 575 hp street deal, I'm short a little on cam duration but I'm fine with this. For the money I've got in the cam/lifter set, I think it'll work just fine.

The 468 ran fine, but was always a mismatched combo with a stock replacement type cast piston. The compression ratio was a whopping 8:1 with the big chamber heads... And I had stuck a fairly large flat tappet cam (244 @ .50") in it. From the E.T.'s it ran while running out of fuel in high gear, the engine made right at 400 HP.

[RatPwrd72]

Originally Posted by ptc

Straub is a great source of info... listen intently!

If you want to stay with iron heads why not go with the 990 rect ports? they will give you more RPM than the 049s if you go to a bigger cam.

Im running a 496 powerplant in my prop boat that is about 700 hp, the 990 heads, dual quad tunnel ram, port matched, Comp cam mech flat tappet cam, Crane valve train parts, SCAT and Crower rotating assembly. SRP pistons 10.25;1 CR on pump gas.

I get about 6900 rpm out of this engine, its instant on the hit and then runs out well. Thinking about the same build for my pro-street truck build.

The 990 heads are great for an all out drag motor or a high winding combo in a lighter weight vehicle. The runner size of the square port heads is way too big to make optimal torque in the "street" range, (2,500 - 5,500 RPM).

I've got a set of 990 heads that were ported by Reher-Morrison in the early 80's on top of a 13:5.1 468 engine with a Herbert solid roller that makes 730 HP at the crank with a single Holley on gas. Peak power is made at 6,800 rpm and it works great on the track, but wouldn't be much fun on the street.

[RatPwrd72]

Originally Posted by bbcmudtruck

I can't speak for the op, but for me, I wanted a street motor, not a race motor. I simply didn't want to spin the motor that high. I'm absolutely sure you could gain more hp in the upper RPM range, but that will cost you torque in the most used rpm range. I'm building my motor to peak around 6-6200k. The 049s or the 781s are perfect for that goal. Tons of torque right off idle and will carry it through the entire desired RPM range. For the most part, I see 990s being used in drag cars, where they need the rpms on the big end. For a street driven vehicle that wont see 6k+ rpms regularly, you'd be giving up power where you use it most. The 990s are good heads and absolutely have their place, however for a heavy street bound hotrod, I'd go with the big ovals every time!

Same here, I'm shooting for this deal to be all in about 5,600 rpm, which is the upper limit of the cam's advertised range. This also means I won't have to spend a ton of cash on valvetrain parts to make it live. The big inch, high RPM engines need 10 degree titanium locks/retainers, high $$ valve springs and high $$ pushrods to make them last longer.

[RatPwrd72]

It's been awhile since I last updated this post. After waiting 3 or 4 weeks for my order, I called only to find out the Mahle pistons were on back order and they didn't know when they would be available. I waited another couple of weeks before requesting either a similar piston or a definite answer on the Mahle set. We ended up replacing the Mahle pistons with an SRP 18cc mini dome set and then it all went to balance. The long and skinny is it shipped yesterday, I should have it by the end of the week and get the Pistons to the machine shop for the final block prep. Maybe it won't be long now.

[RatPwrd72]

Everything went to the machine shop the 3rd week of May so he could finish the machine work. We discovered the #2 main journal .004" out which we resolved with a line bore. The deck of the block required a little more off of it than planned to get everything squared up which meant we're right about 10.4 for the compression ratio. I didn't snap many pics during the file fitting of the rings or bottom end assembly, but here it is as a short block last week.

Here's the clearance necessary for the rod and rod bolts in the bottom end.



ARP bolts in the Scat Pro-Comp series rods




Pistons installed and short block complete.



The gently used Crane hydraulic roller and lifters were up next, here's the lifters soaking after checking and cleaning before install.



Here's the long block before the intake and balancer were on. The 049 heads got new valves, surfaced, a 3 angle valve job and a set of Isky valve springs setup to match the new cam. Also, I had to order the correct Crane pushrods to compensate for the retro roller lifters being much taller. I used the same roller rockers I had before, although a new set wouldn't be a bad idea down the road.

[RatPwrd72]

And about that balancer... It's a Pro Street labeled piece that came from CNC Motorsports with the rotating assembly. While not an SFI approved balancer, it'll work just find for this build with a max RPM of 5,700 or so. This is also the first time ever I've had to "cook" a balancer in order to get it installed. 250 degrees for 15 minutes did the trick and it went on nice and tight. I verified TDC with the timing tab and went on to the next step.

[RatPwrd72]

So after wrapping up all the small details with the engine, it went in the truck a couple of weeks ago. Standard deal... Replaced belts, hoses, new plugs, etc and got it all together. I had been using a modified 3310 vacuum secondary Holley and that's what I started it with. Instantly I knew it needed help, the truck didn't want to idle at all and seemed very rich all around. I heat cycled the engine a few times and set the timing to 36 total, 14 initial and tried to drive it around the block without much luck. Last year I put a 16 gallon fuel cell and Summit branded electric pump out back with -8 fuel line and always thought the pump was really loud, louder than the Holley Blue pump on the race truck. Now the pump is screaming and after checking the fuel psi, it's only making 3 psi...

I stuck a new Holley HP150 in its place and its night and day difference. Steady at 7 psi and much, much quieter. Also, I just happened to have access to a new in the box AED 850 HO that I was able to try. Initially I thought the mechanical secondary carb wouldn't offer much drivability on the heavy truck but I was wrong. Very responsive with no bog at all. Unfortunately the tires don't stand a chance anywhere below 65 mph.

I do have a little valve train noise, probably from the hydraulic roller lifters and my Moroso stamped steel covers amplifying that. The engine has Valvoline VR-1 20/50 in it for break in purposes, it was suggested to switch to a 15/40 oil to help quiten them down according to the guys at Crane. They also said a little noise is acceptable...We'll see after I get a few miles on it and do the first oil change. I set them with 1/2 turn preload, the Crane guys also said a full turn might be necessary...

So far I broke the transmission mount and discovered a weak u-joint while tuning the carb and timing. And the tires were spinning both times....

[Captainfab]

Subscribing