Circle track 388 vs. 406 vs. 6.0L

[jtb032295]

Alright, don't take this in the wrong way. I would rather not throw out a budget number because I feel it changes the types of comments that this thread receives and next season's budget really hasn't been made yet...

A budget is hard to pinpoint when the build is going to progress later down the road. The driver is not the best at a modified yet, but he has been driving and winning in the previous street stock class. He knows how to drive but we've been around circle track racing long enough to know that if you're setup is wrong, you'll feel like you're down 50HP.

[ProPower engines]

It's really hard to give suggestions on any combination with no rules per say and no idea of what direction you want to move in.
That said there is many options available so all I can suggest is get the best parts you can afford

[jtb032295]

It's really hard to give suggestions on any combination with no rules per say and no idea of what direction you want to move in.
That said there is many options available so all I can suggest is get the best parts you can afford

Completely understandable.. I guess my hope was to build the 388 bottom end with the best we can afford, throw our heads on it with a solid roller and go racing for now. That will surely be a big improvement over the engine we have now, considering it's still a hydraulic flat tappet... Later down the road maybe throw a good set of heads on it?

[RCJ]

Put some spayed main caps on your 350 block.I would use a 3.5 stroke compstar comet lightweight crank, small journal, compstar rods,a good piston with .043 rings.This short block will be easy to up grade later on with a roller and heads.I would use a brodix track 1 head,I've used them a lot in the past and they always perform well,Edelbrock 2925 intake.Roller cam 260/264 @.050, 106 set in at 102 is common ,I've had good luck with 110 set at 106 with a hard tire

[racear2865]

Build the 388. Heads will work. Not the best but will do. Cam grind 106 or 107. Run straight up or even retarded until driver learns then advance cam. Start on gas and go to methanol if you have enough compression. Start with too large of carb to soften off the turns until he learns to drive then carb correctly. Play with spacers under carb to fit driver. A lot depends if they have tire rule.
reed

[MaxFlow]

It's not the cubic inches that wins dirt races! Cars and drivers win at these venues. Don't worry about building an engine until you are holding what you have WOT all the way around. My 100hp honda can run over 100mph. Takes a little longer to get there, but once there can maintain that speed even up 3% grades.

I'd put a basic lunati SR and Track 1 heads with a HV1 intake on a 383 or 388 or 406......it really isn't going to matter much which you build, *whatever is cheapest* and tune on the car til you can run it with your foot in the throttle. You have to maintain your momentum. A big hp piece gives a little more recovery/qualify a little better etc.

AMRA is tough racing. Mullins, Pro Power, Malcuit, Draime, Gaerte, etc are all competing and have failed to qualify for the A mains many times. A reliable engine, a great car, and a GREAT driver is what it takes.

[MadBill]

...Thanks for the help guys, I know posts like this are hard to deal with.. I didn't wanta be that guy but I need some direction..

My suggestion would be that once you've come up with a fairly detailed plan and major parts selection, but before you buy them, talk to a custom cam grinder such as camking* here on SpeedTalk for his recommended (presumably a solid roller) cam specs. He might have some suggestions re changes to better utilize his stuff and at a minimum can provided lobe lifts @ TDC for speccing valve reliefs for the piston supplier.

* I'm no wizard builder, but I've been involved with more than half a dozen engines using Mike Jones' inverse roller flank cams and every one has been an out-performer. Since each cam is a one-off custom, he does get backed up from time to time, so if you go with him, plan accordingly.

[Krooser]

Dirt or pavement?

On dirt the IMCA type modifieds are split between open and crate motors with most guys around here winning with crates... if the track turns dry slick you can't use the horsepower. 400 HP+ seems to be enough.

That said I'm not a fan of crates...

Build the best set of heads you can... get a custom cam from one of our cam gurus here like Mike Jones. A 383 is a good combo. Compression is horsepower... look at using methanol if you are good at routine maintenance.

Some of the import rods and cranks are good... Scat, Molnar, K1. Buy the lightest pistons you can afford with gas ports and a hard coating if you run alky. A good GM steel forged crank will live at 550 HP for a season or two.

Get the chassis dialed in and get the driver running smooth with an easy touch with the throttle and you should be fine.

[jtb032295]

It's not the cubic inches that wins dirt races! Cars and drivers win at these venues. Don't worry about building an engine until you are holding what you have WOT all the way around. My 100hp honda can run over 100mph. Takes a little longer to get there, but once there can maintain that speed even up 3% grades.

I'd put a basic lunati SR and Track 1 heads with a HV1 intake on a 383 or 388 or 406......it really isn't going to matter much which you build, *whatever is cheapest* and tune on the car til you can run it with your foot in the throttle. You have to maintain your momentum. A big hp piece gives a little more recovery/qualify a little better etc.

AMRA is tough racing. Mullins, Pro Power, Malcuit, Draime, Gaerte, etc are all competing and have failed to qualify for the A mains many times. A reliable engine, a great car, and a GREAT driver is what it takes.

This. I completely agree and that's what we've been doing in the street stock division for the past 6 years. Build a reliable engine and keep up the corner speed.

Krooser,

This will be dirt and the track does turn dry slick in the summer months. I've pretty much decided on building the 383 combo for next season with a Scat 4340 crank, Scat Pro Comp I beams, and SRP-329453 pistons (I'll look into gas ported pistons). Depending on how next year's sponsors work out, either rebuild our Sportsman II's or purchase a set of Track 1's. A good solid roller with either choice. We're still working on the chassis, getting closer every week.


Random question on the Sportsman II's, how much would it be holding back if I had these heads flowed and they tested relatively well? I know it all depends on the actual flow numbers but by looks, these heads were professionally ported. They are perfectly gasket matched to a 1206 gasket, have a little taken out of the roof, pushrod pinch layed back and sleeved, and a 2.08" intake valve installed. The exhaust port also has work done, but it's not as obvious.

[Krooser]

It's not the cubic inches that wins dirt races! Cars and drivers win at these venues. Don't worry about building an engine until you are holding what you have WOT all the way around. My 100hp honda can run over 100mph. Takes a little longer to get there, but once there can maintain that speed even up 3% grades.

I'd put a basic lunati SR and Track 1 heads with a HV1 intake on a 383 or 388 or 406......it really isn't going to matter much which you build, *whatever is cheapest* and tune on the car til you can run it with your foot in the throttle. You have to maintain your momentum. A big hp piece gives a little more recovery/qualify a little better etc.

AMRA is tough racing. Mullins, Pro Power, Malcuit, Draime, Gaerte, etc are all competing and have failed to qualify for the A mains many times. A reliable engine, a great car, and a GREAT driver is what it takes.

This. I completely agree and that's what we've been doing in the street stock division for the past 6 years. Build a reliable engine and keep up the corner speed.

Krooser,

This will be dirt and the track does turn dry slick in the summer months. I've pretty much decided on building the 383 combo for next season with a Scat 4340 crank, Scat Pro Comp I beams, and SRP-329453 pistons (I'll look into gas ported pistons). Depending on how next year's sponsors work out, either rebuild our Sportsman II's or purchase a set of Track 1's. A good solid roller with either choice. We're still working on the chassis, getting closer every week.


Random question on the Sportsman II's, how much would it be holding back if I had these heads flowed and they tested relatively well? I know it all depends on the actual flow numbers but by looks, these heads were professionally ported. They are perfectly gasket matched to a 1206 gasket, have a little taken out of the roof, pushrod pinch layed back and sleeved, and a 2.08" intake valve installed. The exhaust port also has work done, but it's not as obvious.

You're on the right track...

[rebelrouser]

don't build any circle track engines, but I have buddies that race sportsman type cars. I know what combinations they are running. You said that an after market block is out of the budget? In my experience with the power level todays heads and cam can make an aftermarket block is the cheapest way to go, if you look at horsepower made and reliability. I build drag race, mud truck, boat, and truck pulling engines. If the rules allow I always run an aftermarket block. The engine lasts longer, and makes more power with every combination I have built. My personal race car is a 512 RB mopar, with a stock block my engines were lasting two or three seasons before being rebuilt, I never blew one up, but I always had to discard the stock block because of cracks, distorted cylinder walls, etc. I purchased an aftermarket block for the cost of the machine work I spent the last three engines, the aftermarket block had been freshened twice in the last 10 years and I really did not need to do it, every thing was just like it was assembled. So what is really more expensive for your race team?

[racear2865]

Im in the process of building an engine for a customer that has basic same rules. He had cast iron heads also and 3.75 stroke. As the track dry slicked, torque became an issue. Also with cast iron heads, had to match same weight on rear to keep percentages in check. I went with aluminum heads so I could shed the weight off front then I chose 400 block with 3.625 stroke to dampen torque. I will advance cam in spring when wet and go straight up or retard on dry slick. Compression set at 14.2 therefore have option on methanol if I need more torque in spring and go to gas in dry slick. Have 3 size carbs to try on dyno to further tune. Can change cam timing in 30 minutes. Gearing can be an advantage if driver knows how to drive and use it. Also set MSD6 up with different slew rate if u need it.
reed

[David Vizard]

My ten cents worth here is to ask just how much power the tracks you may race on can hold if there is a tire rule. I have had to deal with an overly powerful engine on loose track and it is not the easiest thing to manage. In fact driving fast with unstudded tires on snow seems a might easier!

DV

[jtb032295]

My ten cents worth here is to ask just how much power the tracks you may race on can hold if there is a tire rule. I have had to deal with an overly powerful engine on loose track and it is not the easiest thing to manage. In fact driving fast with unstudded tires on snow seems a might easier!

DV

David, thanks for the input... However, that is a really good question and can be hard to answer. The tracks that we run on can change dramatically week to week and even more as the seasons change. In the spring/early summer, the track is usually nice and tacky and can use all of the engine. Towards the summer and late season months, the track ends up slick/dry slick by the end of the night.. Long story short, if I had to guess, I would say 500-525HP is a good number to shoot for. It may not be the greatest when the track is really tacky and full of grip, but it would be a good engine to learn with and power can then be improved upon in the future.

[sanfordandson]

My ten cents worth here is to ask just how much power the tracks you may race on can hold if there is a tire rule. I have had to deal with an overly powerful engine on loose track and it is not the easiest thing to manage. In fact driving fast with unstudded tires on snow seems a might easier!

DV

David is spot on. Make a smooth driveable motor. Thats why the crates do well, tiny cam with a broad powerband.

Imo a 383 type engine is to peaky. I'd build a stout 360ci 3.5 stroke motor. I've seen the 604 crate even win on tacky half mile tracks. Dont get to carried away with hopsepower.