When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Organized Drag Racing and AutocrossDrag racing and autocross discussions and questions. Techniques, tips, suggestions, and "what will I run?" questions.
What a fun time that 385 build was. To run mid 10s conisitanty was such a blast and came to a scratching halt last weekend when a rod let loose at 125mph and thankfully I kept the car off the wall and made it safely to a stop. Some carnage pics are below. I'm assuming these weak forged sir rods are the reason it all came to break.
Lesson I've learned is over build everything. I never thought I'd run 10.70s so easily with a sbc. If I knew it would have ran so well I would have beefed up the internals to better forged stuff.
So now we move on to a bbc. I rebuilt this motor for a friend last year then he broke is rear end in his chevelle and wrecked at the track. So he let me use this motor to see if I wana buy it.
This big block fit in the engine bay like it was ment to be there. I didn't have to change anything. Although these headers I'm going to start building are going to be a bear.
Engine specs below. This block and engine is strong enough that it will last me a long time and gives me alot of room to grow in the future.
merlin ii block
grumpy jenkins iron 345cc heads (366cfm@.600)
forged rotating assembly with h beam rods.
merlin single plane intake.
hardcore 870cfm carb (adding a proform main body)
1.7 roller rockers
9.5:1 comp
minimum 540hp/575tq
crane 296 cam. 236/246 dur at .050 3000-6600rpm. Little under. 600 lift.
Update. Well it's been a month since the blown up engine. Not doing so well this year in the pro class. But the big block 509 is ready to race Sunday at last. Added some pics. I built the headers forward facing as they were just plain old easier to do. Took about 20 hrs in all to build weld and wrap. Are built individual so when the wraps off you can take one tube off at a time lots of slip fit joints and single flanges.
hoping to run some conisitant passes. PTC said my converter should be ok with this big block. My only concern is top end rpm with such a small cam. Adv.296/306 dur at .050 236/246 .554/.571 lift. Basic rpm 3000-6600. If I trap 123-125mph like I did with the small block I'll be pushing 6500-6700rpm all day long. I just hope k dont have valve float.
I did add a few things like a elec. Water pump. Brawler race 950cfm carb, and also some areospace front drag brakes that I've head for quite awhile, just didnt have time to toss them on before.
I have a new bolt together billet converter on the way and also a top end kit from chris straub. Solid roller, promaxx heads, victor jr intake port matched...exc. our end goal is 700hp minimum but more likely 750 or so hp crank. This will be this winter's project.
I'll be getting a different trans as well when I make the move to the straub stuff. My current th350 is only rated at 650hp. The 509 currently puts out about 550hp 600tq give or take. Very very mild.
I'll be sure to post up some slips vids this weekend as long as the weather holds out. Let's hope I can win some rounds.
i will add i wont be using my transbrake because I'm scared it may kill the current th350 i have. Footbraking time. Keep in mind my stall is 5000rpm. 8 inch ptc
What a fun time that 385 build was. To run mid 10s conisitanty was such a blast and came to a scratching halt last weekend when a rod let loose at 125mph and thankfully I kept the car off the wall and made it safely to a stop. Some carnage pics are below. I'm assuming these weak forged sir rods are the reason it all came to break.
Lesson I've learned is over build everything. I never thought I'd run 10.70s so easily with a sbc. If I knew it would have ran so well I would have beefed up the internals to better forged stuff.
What RPM were you turning? Eagle claims those rods are safe to 7000 rpm.
I have a set in a 302 SBC that easily turns 8000 rpm. Do you think the rod was too weak, or an associated problem caused the failure?
Or no way of ever telling?
The 302 uses a 3.000" stroke, so there is less rod angularity compared with your 385 (3.750" stroke).
Last edited by NoEmissions84TA; 07-27-2018 at 01:27 AM.
What RPM were you turning? Eagle claims those rods are safe to 7000 rpm.
I have a set in a 302 SBC that easily turns 8000 rpm. Do you think the rod was too weak, or an associated problem caused the failure?
Or no way of ever telling?
The 302 uses a 3.000" stroke, so there is less rod angularity compared with your 385 (3.750" stroke).
Honestly it looks like I spun a rod bearing?? See the discoloration on the crank. But i cant be sure. I was turning 6600rpm trap and I'm guessing 525hp so those rods were a little over powered 5140 rods. The car was open headers so it was loud and made a 10.63@126mph pass the run before it blew so I had no warning this was going to happen. I was on another killer pass when it litterly locked up at 125mph right at the finish line.
the 509 is race ready and thankfully my v6 springs are holding up the big block decent.
Well here is the update on the winter build. Adding some goodies this winter. All of it was from straub technologys. Chris over there and I plan on this being 700-750hp for a goal. Shift point of 7200 and a peak hp of 6800. Should make for a fun pro car. Cam specs below. Decent size solid roller conversion. New promaxx heads that were milled to 114cc chambers and assembled by struab.
Compression will be 10.1:1 so it's a nice pump gas street car set up still.
I have a bolt together super 8 tsi converter for this set up, 5500rpm is our goal on a flash stall.
I'll keep this updated as the winter progresses. Right now I have a merlin 509 bbc. Runs 11.10s@120mph. Very small cam and very mild over all. So the new parts should help me get down that track. The engine itself if built solid and will take a solid 1000hp if we wanted to.
Specs on the heads I have. For some reason I thought chris said 320s but it was indeed 317cc. Not too bad. Shouldnt be hard to reach that 700 750hp goal.
Update well I'm finally selling my first home or renting it to move into a new house. Georgous house in the woods. And of course a nice 30x40 shop for me. So needless to say I'm leaving the Camaro in running condition for another few weeks. Our closing is Nov 9th and well be moving that day! After that...700hp plus bbc build here we come.
Update I'm tossing all the straub goodies on now. Going quite well.
Reminder this is a merlin ii block. 4.5 bore 4.0 stroke. 509ci.
all forged rotating assembly and built to take from what I've read, a minimum of 1000hp. We are planning to stall at 5500rpm and trap 7200 rpm if it runs around 137-139mph.
I'm adding a 2 piece timing cover, arp head studs over the manley bolts it had, true roller billet timing set, arp fasteners throughout. Had manley before. Custom bullet cam, promaxx heads, ported and matched victor jr intake 4150, custom length pushrods, morale sportsman pro solid roller lifters, straub 1.7 roller rockers, etc list goes on.
I weighed the old iron heads 82lbs each. The new 317cc promaxx are 42lbs each. So we are saving a solid 80lbs. Not too shabby in weight alown. At least I'll be back into the 3400lbs race weight area. Still heavy imo.
In about 2 months I've gotta race this car and hopefully keep it at 10 flat or higher. I have a feeling itll be faster and if I cant slow it down enough we will have to get s nhra licence change up some safety items etc. Keep in mind it ran 10.70s@125mph with a 525hp 385ci when it weighted 3360 race weight. Add a solid 200 hp and about 500lbs.. who knows.
For the life of me it's hard to get the quench down to where I want it on this block. The total quench at the end is .052 which I dont like but chris straub says its fine so well go with that. The compression is now 9.8:1 up from a horrid 9.1:1.
straub milled the heads down to 115.2cc chambers.
This straub technologys kit from chris is goal oriented to make 700hp+ solid roller billet. Port matched heads, intake, promaxx heads all assembled etc by Chris as they were bought bare. Flowed at 380-390cfm at .700 lift.
I will be running a ATI 850hp rated th350 with a super case. SFI cert. I went over this build with david from ATI many times and we decided on this trans because of simplicity, weight, strength(300m input, 36 eliment sprag, any thing you can do is done) and it was a bolt in 9 inch tail. ATI compu-flow transbrake etc
This is coupled to a custom TSI spragless super 8 bolt together tq converter. Billet etc built for 5500 stall with engine, chassis combo.
The 509bbc is up and running. I really wish the weather would cooperate.
I will say I'm excited to see what this thing runs although I am a little nervous because if it runs under a 10 flat I'm going to have to get a chassis cert and a NHRA license.
I will be sure to update you all the 1st few times I run it it will be off the foot brake and not trans break. Chris syraub said that this set up was designed for 700 minimum but more likely 750-775 horsepower. Everything else I set up for this to trap about a 135-140mph. Hopefully crossing the stripe at 700-7200 rpm. Which is the peak designed hp on the cam.
The car should way in right around 3380 raceway but we shall see as I added something such as an alternator Some more bracing on the frame etc.
It's been a while so I wanted to update. The 509 is a solid mild set up. Best of a 10.35@129mph with a 1.41 60. Best 60 ever is a 1.40. Not too bad for 3575lbs race weight 3365 on a scale w/o driver, and a 509 with 9.5:1 static comp (corrected and checked)
Did well at the track once I figured out the whole launching with a t brake etc.
Here is one of the only vids I got. Sideways.... and lb3a. But this is a solid pass else then that enjoy
Been a long while since I've updated this thread. Set ups been solid for a few years now. Just coming off a rebuild. Nothing new just rings bearing etc.
It did squeeze off some 10.10s this year. Best of a 10.17@131.
Well it's been awhile since the last update. Like any car it has evolved a bit.
It is now a 540bbc. I wanted to keep it pump gas, the static comp is about 10.3:1. Runs on 91 octane.
Very mild and smooth. Got to race alot this season and overall it did well. Car still weighs about 3525lbs with me in it. Although I already shaved 60lbs out of it this fall, new fabricated dash, removed speakers, etc but still retains a factory looking interior minus the dash. Best 60 foot was a 1.27 on 9 inch pro braket radials on a good track. Trans brake launch. Best 1/8 mile was a 6.22@109mph Best 1/4 mile was a 9.94@132mph which I foot braked the launch, traction was tough on a marginal track with pbrs. I feel we could go faster. Again the main issue was traction. Even with da shocks, limiters etc. Radials on these no prep or marginal prep tracks I went to, just don't cut it. So they are gone never to return. We are going with 28x10.5 slicks for next year in hopes we don't loose so many braket races from track conditions.
Traction. It's always about traction. High HP means nothing if you can't get the power to the ground. I laugh when these drag radial or small tire classes brag about how fast they can go. Of course they also go that fast during big competitions and on a well prepped track. Try running those times on a typical street legal night with minimal track prep.
It took a lot of effort to back half my car to stuff a huge tire under it but it was worth it. Even on poor tracks, I've still lost traction but not as bad as the small tire cars were doing.
Bumping your tire up to a 10.5 will be a noticeable difference. If gearing and fender space allows it, go to a 29 or even 30" tall tire. A taller tire will have a contact patch on the ground for a longer period of time which will provide more traction. In bracket racing, you spin off the line and you've lost the race. Speed means nothing. It's all about consistency.
The car is ready for spring else then the new slicks. I am waiting on a set of 28x10.5 hoosiers. I borrowed a buddies and they fit well. It's tight but there is room. I agree 100% radials seem to be fast but it's not worth it in bracket racing. I've used the same size radials from when the car ran 12s. It was definitely time to go to slicks and larger ones. I felt that even with all the adjustability of the da shocks and what I've learned, it meaned nothing when I would go to a no prep track or marginal track. They either hook or not. Very flustrating. I think the Slicks will be much easier for a beginner suspention tuner like myself.
I laugh because when im in the pits and look arround at all the cars in pro and super pro that run under 10 flat, not one had radials let alown a tire as small as me. I was trying yo make something work that is just not consistant. Especially at the smaller tracks that I go to, that had glue shortages last year.
Providing there's an index window for a class like 10.00-11.99 seconds, you would like to be right near the bubble at the bottom end of the scale as the fastest car in the class. In a bracket race, your opponent will always launch first so your first chance of winning a race will be if they red light or not. After that, you just have to chase your opponent down to the finish.
We spend more and more money to go faster and faster. Where else do you spend as much money to spend less time behind the wheel?
I always get that thrill of the launch. There's always butterflies going into first round but if I get into second round, it's just relax and do the same procedure again and hope for the win.
Now if you're in a heads up race, speed really means money and the faster you go to be the faster car, the more you need to spend. I've mentioned that a typical street car can throw a 150 HP NOS shot on they're car and they could pick up 1.5 seconds in the 1/4 mile. If I threw a 150 shot of NOS on my car. I might pick up 0.2.
In a bracket race however, speed means nothing and the more consistent a vehicle is, the easier it is to win. I've raced in a King of the Hill type race where all vehicles are lumped into one class. It goes to show who is the better driver and knows their car. Slow cars are hard to beat. Best race I saw was a husband and wife team. He drove a car show mint 1967 Fairlane that could run 12.0 all day long. She drove a 21 second Festiva. When they got paired up against each other, she had a 9 second head start down the track. Both got green lights and she has closer to her dial in and won. I think she was around the 1/8 mile mark before he launched. Crowd loved it.
I love running in the faster classes because it allows me to do more things to the car. I use a delay box and launch off the top yellow bulb. If I ever get a red light, it was my fault and not the cars. Providing how I have the delay box set up and how I react to the lights, I rarely get a reaction time worst that 0.025. Throttle stop also allows me to sit on the starting line with the throttle pedal pushed to the floor and the engine is still at an idle. So much easier with consistency. If I really wanted to, I could hook up the air shifter and let the rpm switch do my shifts at the exact same rpm as well. So many of these things you're just not allowed to do in the slower classes. I could never be a footbrake racer launching off the bottom bulb again.
I even tried a 0.400 Pro tree a couple of times. That's really hard to get a good reaction time. The vehicle needs to be super quick off the time to do that.
06-25-2018, 05:34 AM
