BBC build- Don't tell the Admiral

[Tail_Gunner]

Are the vortecs oval port or square ports,do you know the valve size?. Now a bit off topic what is the final gearing......and prop sizing do you have a or does that drive have a large selection available.....this engine will change the dynamic's just a tad.

 

[Scott Danforth]

currently working out the logistics of my trip to Wisconsin to pick up a set of heads, a running high-mileage core, my engine hoist and my engine stand...... as well as catch the end of the walleye season

Wife wanted me to wait, however I am also tying this in with visiting customers (yacht builders) so the fuel and lodging is paid for by the company.

I love it when a plan comes together.

 

[Scott Danforth]

Are the vortecs oval port or square ports,do you know the valve size?. Now a bit off topic what is the final gearing......and prop sizing do you have a or does that drive have a large selection available.....this engine will change the dynamic's just a tad.

the vortec's are small chamber (99cc or 100, depending on casting) large oval with 2.07 and 1.72 valves. they flow great up to 5500 RPM. google L29 heads. they flow as much as the 049 mark IV heads

as far as props, I have both B5 and B6 props, the B5's will need to go, as I spun those past 5000 RPM all day long with the SBC. the B6 was hitting 4800 RPM when I pulled the SBC. there are also B7's, and the stainless C series, along with the new J series (3 and 4 blade combo). the J-series replaces both the A (diesel) and B series. Plenty of props to pick from.

 

[gm280]

Scott, I can easily see the "bigger is better" syndrome has you in its grips now, and that is okay. Just don't build yourself a constant maintenance engine where you have to work on it the entire week for a few hours of weekend enjoyment. And believe me, I have seen that type engine over and over and over again. I use to help my son with his daily driver/weekend drag race car. JMHO!

 

[Scott Danforth]

Scott, I can easily see the "bigger is better" syndrome has you in its grips now, and that is okay. Just don't build yourself a constant maintenance engine where you have to work on it the entire week for a few hours of weekend enjoyment. And believe me, I have seen that type engine over and over and over again. I use to help my son with his daily driver/weekend drag race car. JMHO!

not going to happen. had that as a daily driver in college, 330hp naturally aspirated 3.8 liter in an opel GT.

This build will be a reasonable displacement fairly mild build with emphasis on stout components not being taxed. the shortblock will most likely be capable of 700+ hp without problem. the heads and cam will run out of breath at 5500 RPM

 

[alldodge]

Found this on OSO and is a very good read. Discusses a 502 build and runs it though several pulls just to get data on changes. Even got into fuel causing some real issues from one vendor to another. Going to keep this one book marked

http://www.offshoreonly.com/forums/...d-502mpi-intake-502-dyno-session-my-shop.html

 

[Scott Danforth]

Found this on OSO and is a very good read. Discusses a 502 build and runs it though several pulls just to get data on changes. Even got into fuel causing some real issues from one vendor to another. Going to keep this one book marked

http://www.offshoreonly.com/forums/...d-502mpi-intake-502-dyno-session-my-shop.html

Im still following this recipe slightly http://forums.iboats.com/forum/engi...101672-bbc-build-don-t-tell-the-admiral/page5

differences, I will be using a 4.25" crank and the L-29 heads vs the 049 heads that I assume PPT is using. the increase in stroke will give me some extra torque, the flow numbers between the heads is about the same up to 5500 RPM, so I should be able to hit the 450hp mark easy.

 

[alldodge]

Sounds good, just a good read to see how things changed. I really like the part where the highly praised flame arrestor did worst they all of them, and the stock Gen V arrestor did better then any of them. They no longer make the Gen V (with center filter removed) so if you have one and can use it, this would be the way to go.

You could also slap 502 heads on the 454, may not be the way to go, just an option.

 

[Scott Danforth]

my motor will be 750 CFM carb sitting on an air-gap intake with a 2" spacer if I have the room, so the stock Gen V and Gen VI marine spark arrestors will do me no good. I will have a big diameter marine rated flame arrestor

 

[Tail_Gunner]

Something odd going on with bb running 500 hp....a lot of guys use single plane intakes..it appear's velocity is not as key and volume is in that hp class along with shorter intake runne's..just a thought. I to believe this a conservative well thought out build

 

[Scott Danforth]

So, I have now been up for 37 hours. Went to work, then drive straight up to the land of Beer and Cheese. Will also be attending Grandmas funeral.

Sis was supposed to pick up the motor, however the ecm in her truck decided to go TU.

So, had the salvage yard strip off most of the stuff I won't be using, including unbolting the intake, then stuffing it into the back of the blazer.

Stopped at my storage unit to get my engine crane

 

[Scott Danforth]

I gots me a gen 6 high mileage runner. However with the miles, it's considered a core

 

[Scott Danforth]

Pick up the low hour heads on Monday. Now I just need to get my engine stand back from Kyle (who now lives in Minnesota for Polaris)

 

[Scott Danforth]

Motor loaded in the S10 Blazer for the ride back to Florida. Also hauling a set of low hour BBC heads off a Merc 7.4

 

[Scott Danforth]

Well, Here are photos of the motor being loaded, and the engine hoist as well.

(photos lost because photobucket execs lost their mind)


drove 3 hours thru the white "stuff" to get to dry concrete. Drove about 20 hours before handing the wheel over to my Aunt to get some sleep. Got home yesterday afternoon and used my salt-away to rinse everything prior to washing it since it was crusted in road salt.

picking up another engine stand tomorrow. Tear down begins this weekend.

 

[alldodge]

Glad ya made it back safe.

Look forward to the tear down and no more pics of the white stuff

 

[Scott Danforth]

Been over a week since the last update. Been chasing new kitchen cabinets for the Admiral. She want what she wants. I have been to 6 different custom cabinet places to find her the dream kitchen she wants on the budget that is still boat/car project friendly.

Wednesday, pulled the motor out of the blazer, have it hanging from the engine hoist right now. looked it over, realized that this block doesnt have the pump pad like the last Gen 6 I looked at. So throwing the mechanical fuel pump on CL, bought an electric fuel pump (should arrive shortly)

In keeping with the budget theme, I have been looking at every website I can for obtaining BBC parts for the build.

I can save a ton of money by keeping the stroke 4" and using the existing stock crank, however its go big or go home. Summit still has the best pricing I found to date on a scat rotating assembly. going internal balance on the crank if I go stroker. Also going forged crank if I go stroker. then will be going to a steel billet flywheel. Can get aftermarket cast versions of 3991469 for under $80, however I can get a used steel centerforce on craigslist for the same price. figure if I have it balanced and decide to spin it faster than 5500/6000, no sense worrying about anything on the parts slogging around.

checking with machine shops to convert the non-adjustable gen V/VI rocker to the adjustable valve train by drilling out and taping the existing rocker stud bosses to 7/16"

 

[Tail_Gunner]

Tinkeritis can be over whelming, speaking for myself i am going with a flat tappet cam large oval port heads with some porting and stroke it. Im shooting for 475 hp and a rev limit of 5500 it seems 5000 rpm is the glass ceiling so to speak above that thing get really costly. Take your hull into drive and hull into consideration...how fast can that hull run safely and how much tourqe and rpm can the drive sustain. Below is my newest project im starting with a 300hp 454 half of my battle is done i really think your going down the right path with a big block there is just no substitute for big block tourque on a larger boat

 

[Scott Danforth]

I know from talking to the folks at cruisers that my hull will be stable to well over 70mph with the right motor. they tested it in the mid 80's with merc racing motors (I believe 525's)

 

[Scott Danforth]

Tail_Gunner , what vintage BBC? Mk IV, Gen V? I found a Gen VI core because I have decided to go roller. plenty of used 049 heads for the Mk IV for under $300 a pair

Since a few sites have the Gen VI putting out 428-430hp on a dyno with nothing more than a cam (XM284HR), lifter, and spring change with stock internals at only 5200RPM, 475 should be obtainable even without stroking with the other changes you are describing. http://www.superchevy.com/how-to/en...power-on-a-junkyard-454-with-simple-cam-swap/

Adding a stroker, some head work, and a bit more compression will make 475hp easy