SB Road Racing/Nascar/Sprint Car/Reving BUDGET BUILD

[273]

This a basic 360 build is stock 5.9 magnum vs adding heads and cam for 319 vs 448 hp @ 5800 rpm, just the cam change without the head swap would of been around 400 hp @ 5400. rpm.

https://www.motortrend.com/how-to/hrdp-0804-small-block-mopar-engine/

Dyno ResultsMopar Magnum 360SuperFlow 901 engine dynoSTP correction factorTested at Westech Performance Group

RPM	Base TQ	Mod TQ	Base HP	Mod HP
3,000	398	37.31	228	212
3,200	410	373	250	227
3,400	419	390	271	253
3,600	424	402	290	276
3,800	420	408	304	295
4,000	412	412	314	314
4,200	396	420	316	336
4,400	381	431	319	361
4,600	362	432	317	378
4,800	346	434	317	397
5,000	328	434	312	413
5,200	298	433	295	429
5,400	274	426	282	438
5,600	-	417	-	444
5,800	-	406	-	448
6,000	-	361	-	412

 

[SRT_DSTRHOLC]

Here is a question for ALL of you.

What are the pros and cons of making power in HIGHER RPM vs the pros and cons of making power in the LOWER RPM range? (Aside from racing class rules)

 

[273]

What is the article for this one?

https://www.motortrend.com/how-to/0901phr-mopar-318-magnum-engine/

 

[SRT_DSTRHOLC]

https://www.motortrend.com/how-to/0901phr-mopar-318-magnum-engine/

This is a great build, but definitely on the upper budget side. I do like the information in there though about the lifter and oil galleys to help with the wear over time. I haven't read the sticky, but this seems to be possibly part of what is in there.

All great ideas!

 

[273]

Here is a question for ALL of you.

What are the pros and cons of making power in HIGHER RPM vs the pros and cons of making power in the LOWER RPM range? (Aside from racing class rules)

Say they make the exact same powerband/curve over 4000 rpm range 1st 2000-6000 rpm and 2nd 3000-7000 rpm then if geared right they should be fairly similar.

As for 318 vs 360, One thing for the 318 is smaller engines then to make more usable power after peak hp cause is harder to under head them, which can come in useful at the end of a long straight or stay in a gear a little longer. Not saying that makes the 318 better choice.

 

[SRT_DSTRHOLC]

Say they make the exact same powerband/curve over 4000 rpm range 1st 2000-6000 rpm and 2nd 3000-7000 rpm then if geared right they should be fairly similar.

As for 318 vs 360, smaller engines then to make more usable power after peak hp cause is harder to under head them, which can come in useful at the end of a long straight or stay in a gear a little longer. Not saying that makes the 318 better choice.

so in the end the lower rpm and higher rpm power is really just because of the displacement and or class rules?

 

[273]

so in the end the lower rpm and higher rpm power is really just because of the displacement and or class rules?

In general yes, in a highly competitive racing class all the little advantages make all difference but outside of that not so much.

Nascar is so expensive because of all the R&D looking for tons of little fractions of advantage within the rules.

 

[Mattax]

Yes, I understand this as a miata with low power can run circles around some other cars because they can carry the weight through turns (go kart). This car has full coil over front and rear with watts link rear. The car has all of the UST Weld on items as well and a full road race inspired cage

I'll add to RRR reply. Dirt track, not Miatas. Miatas had a fair amount of body roll, not like a go kart in that sense at all. They had poor torque off the line, good higher up. In general they were momentum cars. Lose too much speed - and thats on the driver - and easy to do in an autocrss but also happens on a road course, then as a driver you find out your error when adding gas and the response is less than you wanted. Good feedback to improve ones driving!

Even on a road course like Willow Springs its far more about torque off the corner than top end power. Read Carroll Smith. He spends very little time on engines, so that part is a short read.

One can look at the 1966 Transam, and SCCA A-sedan class of that era for examples of smaller engined cars doing well in the class because they handled better. The 273 was the smallest cid in class. Didn't stop Group 44, or the factory backed teams from being competitive...

Look up Alltime racing and go to an event to get a good sense of street cars, in particular mopars and older mopars, people enjoy driving on the track. Some are, or were, also road race cars (wheel to wheel competition within a class). You don't need to drive to attend.

 

[SRT_DSTRHOLC]

I'll at to RRR reply. Dirt track, not Miatas. Miatas had a fair amount of body roll, not like a go kart in that sense at all. The had poor torque off the line, good higher up. In general they were momentum cars. Loose too much speed - and thats on the driver - and easy to do in an autocrss but also happens on a road course, then as a driver you find out your error when adding gas and the response is less than you wanted. Good feedback to improve ones driving!

Even on a road course like Willow Springs its far more about torque off the corner than top end power. Read Carroll Smith. He spends very little time on engines, so that part is a short read.

One can look at the 1966 Transam, and SCCA A-sedan class of that era for examples of smaller engined cars doing well in the class because they handled better. The 273 was the smallest cid in class. Didn't stop Group 44, or the factory backed teams from being competitive...

Look up Alltime racing and go to an event to get a good sense of street cars, in particular mopars and older mopars, people enjoy driving on the track. Some are, or were, also road race cars (wheel to wheel competition within a class). You don't need to drive to attend.

I just loaded up on a bunch of classic nasar and carroll smith books etc.

The goal is to track the progress of the car from start to finish so I can tune the brakes/suspension as I increase the power. The eventual goal is to get this little ol grandma car to compete with something off the production line today with the same power to weight, but the driver needs some more seat time with old girl first

 

[MopaR&D]

In my mind, these older pushrod V-8s are just better suited to lower-RPM torque due to their valvetrain. It's not like smaller OHC sports car engines where they can physically rev to the moon and generally make hardly any torque below 3000 rpm. You can build an SBM to rev to 7k but you'll need to spend money on making the valvetrain comfortable at that speed. The stroke doesn't have as much to do with its ability to support high revs like smaller engines. The top end also doesn't flow air (relative to displacement) anywhere near OHC sports car engines so money needs to be spent there as well to make power that high up. A 400whp 360 with the right cam and intake will pull just as hard at 2500 rpm as it does at 6000. The torque curve is extremely flat compared to a small OHC engine so you don't need to downshift like you're used to with typical sports cars.

G3 Hemis have the air flow and valvetrain that makes them generally have a powerband higher up than older wedge engines but they still make tons of torque in the midrange. That's why they come in pickup trucks, SUVs and heavy cars. I have a 5.7 I'd like to put in an A-body someday but it'll get a pretty big cam and single-plane intake because a lighter car like that simply doesn't need the low-end torque it offers in stock form. Think of the V10 in the Viper (extreme case), the brutal torque in that light of a car takes a lot of practice to master and make use of without just blowing the tires off. I watched a video by Dead Dodge Garage on YouTube where he was test-driving a classic Challenger with a stock 6.4 and Tremec 6-speed and he couldn't give it much more than 1/3 throttle without losing traction unless he was in 5th or 6th gear. Fun but also a handful and not very useful on a track, would work better with a big cam that softened the low-end torque and moved it higher up in the revs.

Not sure if any of that is useful just thinking out loud lol

 

[SRT_DSTRHOLC]

In my mind, these older pushrod V-8s are just better suited to lower-RPM torque due to their valvetrain. It's not like smaller OHC sports car engines where they can physically rev to the moon and generally make hardly any torque below 3000 rpm. You can build an SBM to rev to 7k but you'll need to spend money on making the valvetrain comfortable at that speed. The stroke doesn't have as much to do with its ability to support high revs like smaller engines. The top end also doesn't flow air (relative to displacement) anywhere near OHC sports car engines so money needs to be spent there as well to make power that high up. A 400whp 360 with the right cam and intake will pull just as hard at 2500 rpm as it does at 6000. The torque curve is extremely flat compared to a small OHC engine so you don't need to downshift like you're used to with typical sports cars.

G3 Hemis have the air flow and valvetrain that makes them generally have a powerband higher up than older wedge engines but they still make tons of torque in the midrange. That's why they come in pickup trucks, SUVs and heavy cars. I have a 5.7 I'd like to put in an A-body someday but it'll get a pretty big cam and single-plane intake because a lighter car like that simply doesn't need the low-end torque it offers in stock form. Think of the V10 in the Viper (extreme case), the brutal torque in that light of a car takes a lot of practice to master and make use of without just blowing the tires off. I watched a video by Dead Dodge Garage on YouTube where he was test-driving a classic Challenger with a stock 6.4 and Tremec 6-speed and he couldn't give it much more than 1/3 throttle without losing traction unless he was in 5th or 6th gear. Fun but also a handful and not very useful on a track, would work better with a big cam that softened the low-end torque and moved it higher up in the revs.

Not sure if any of that is useful just thinking out loud lol

Perfect example of why I want to learn how the car reacts before throwing more power at it. I have the idea setup for suspension and I am still becoming familiar with oversteer and understeer, but I don't want to add power into the mix until I am comfortable and practically bored of more power.


Going straight fast will help me know how to make the power I want, but now I want to blend it into the Trans Am world

 

[rumblefish360]

Love the post.

I should have been more clear. This won't be a race "only" car. I am looking to build an engine from stock to full or mostly aftermarket part and enjoy the process of going from stock to fully modified or not.

Ditto, love the process.

When I say "budget" I mean, I would like to build an engine, regardless of how many times I may have to change the bearings or gaskets, that will allow me to run at the track and enjoy it.

IF I could use all stock parts from any year of 5.9 or 5.2, etc with mix and matching stock parts and then upgrade to a air gap or M1 intake do so. My main idea is to R&D the process of what actually works and doesn't for "my style" of driving and car build.

I know that I could build a full R3 race engine and be good to go, but a lot of people starting out with these cars don't have the money to do that, so I want to go back to my roots of hot rodding and enjoy the process of a single cam change or a intake change or a manifold to header change and see how it effects the car overall. IT is a lengthy process, but to be honest, I like the process progress.

Gotcha! On the same page!

The machine work is something that I am willing to spend money on, but I want to do it in order instead of building the engine from start. I want to do a full car build from ground zero up mainly because the first engine I built was with the EGO of just wanting to go fast. This time I want to understand each part of the process. Also, I have looked at going to school to do machine working, but at the moment, I have no problem paying for that work. Assembly I have done.

I am a person who likes to do my own work, but when I need to ask for help I will, but I enjoy the hot rod process of trial and error

Myself as well. Know it all I am for surely not!

Here is a question for ALL of you.

What are the pros and cons of making power in HIGHER RPM vs the pros and cons of making power in the LOWER RPM range? (Aside from racing class rules)

I don’t know of a RPM limiting class until you get to… NHRA Pro Stock I think it is where Chevy cried a river because they can’t out RPM a HEMI to try to out power the HEMI for more HP.

The con of high rpm high output is accelerated wear.
The con of lower rpm output is a cost lost in HP.

Think of RPM as a hammer hitting a nail. The more times you can strike the mail, the faster you drive it into the wood. This is why guys will chase a high rpm engine. The more times you can get the piston to fire per second is going to provide more power per second causing the car to cover more ground quicker like the hammer hitting the mail faster.

People will build a stroker because the longer stroke is like hitting the mail harder with a hammer. But it will hit the mail less times per second since it takes time to rotate the assembly because the stroke is longer.

Of course it’s possible to build a stroker that will turn 8K, but obviously out of the scope of the build idea and feel.

 

[rumblefish360]

Considering the idea of a grass roots build starting from a simple base power plant, (something I’m setting up to do videos on) I love the idea. It was the way of things when I was starting out with this fun @ 18 years old. I could get a “Not so old” Duster for 2 weeks part time pay @ minimum wage ($3.15 back in the day!) and get a really well used but still in very good shape vehicle.

 

[SRT_DSTRHOLC]

Love the post.


Ditto, love the process.


Gotcha! On the same page!


Myself as well. Know it all I am for surely not!


I don’t know of a RPM limiting class until you get to… NHRA Pro Stock I think it is where Chevy cried a river because they can’t out RPM a HEMI to try to out power the HEMI for more HP.

The con of high rpm high output is accelerated wear.
The con of lower rpm output is a cost lost in HP.

Think of RPM as a hammer hitting a nail. The more times you can strike the mail, the faster you drive it into the wood. This is why guys will chase a high rpm engine. The more times you can get the piston to fire per second is going to provide more power per second causing the car to cover more ground quicker like the hammer hitting the mail faster.

People will build a stroker because the longer stroke is like hitting the mail harder with a hammer. But it will hit the mail less times per second since it takes time to rotate the assembly because the stroke is longer.

Of course it’s possible to build a stroker that will turn 8K, but obviously out of the scope of the build idea and feel.

So then would this mean that having the power lower with a redline of 6500 but power a little lower would make for an engine that would have better durability long term in comparisons to say a engine that has redline at 7-8k?

My engine science knowledge is limited to going fast, but I am re learning how to build the engine from the scientific perspective this way I can determine moving forward the science of cam, intake, engine choice instead of chasing the numbers like most do when new to the game.

 

[rumblefish360]

So then would this mean that having the power lower with a redline of 6500 but power a little lower would make for an engine that would have better durability long term?

Pretty much! The less PM you turn the less stress the engine has. Low stress, low maintenance. High stress, high maintenance.

Stock engines, low maintenance
Hot rods street strip, medium maintenance
Race engines, high maintenance

 

[SRT_DSTRHOLC]

Pretty much! The less PM you turn the less stress the engine has. Low stress, low maintenance. High stress, high maintenance.

Stock engines, low maintenance
Hot rods street strip, medium maintenance
Race engines, high maintenance

I would like to find that line for each. I would like to "personally" know okay with the way I drive this engine I need to replace the bearings after 1 season or 2 seasons or okay, I can push her a little more etc.

I want to learn those things the race teams learn by DOING

 

[273]

I’d just start with a decent running engine just do the basic hot rodding cam 4bbl headers, gear it so it will live on the long straights and go from there, gives you a baseline in performance to plan which direction you need to go. Your 69 if in running shape or magnum 5.2 or 5.9.

 

[SRT_DSTRHOLC]

I’d just start with a decent running engine just do the basic hot rodding cam 4bbl headers, gear it so it will live on the long straights and go from there, gives you a baseline in performance to plan which direction you need to go. Your 69 if in running shape or magnum 5.2 or 5.9.

That's where I am at. Especially since I can always throw the Magnum heads on the 69 etc

 

[rumblefish360]

I would like to find that line for each. I would like to "personally" know okay with the way I drive this engine I need to replace the bearings after 1 season or 2 seasons or okay, I can push her a little more etc.

I want to learn those things the race teams learn by DOING

My kind of guy! I traveled some of that exact route for run myself.

I’d just start with a decent running engine just do the basic hot rodding cam 4bbl headers, gear it so it will live on the long straights and go from there, gives you a baseline in performance to plan which direction you need to go. Your 69 if in running shape or magnum 5.2 or 5.9.

BINGO!!!

 

[autoxcuda]

Here is a question for ALL of you.

What are the pros and cons of making power in HIGHER RPM vs the pros and cons of making power in the LOWER RPM range? (Aside from racing class rules)

RPM = $$$ = valve train breakage = expensive parts to prevent it

 

[autoxcuda]

You need Dougs or TTI headers for ground clearance

And a Milodon road race pan to keep oil pressure and prevent oil pump from sucking air.

 

[junkyardhero]

You need Dougs or TTI headers for ground clearance

And a Milodon road race pan to keep oil pressure and prevent oil pump from sucking air.

don't forget the accusump, baby!

+ $2500 to get it track ready

 

[JunkyJimmy]

I have built afew circle track magnums, a 400 hp, 6300-6400 rpm 5.9 can be built pratty cheap. Valve springs are a must and the ones I built would bend pushrods at them rpm’s, Hughes has some that work well.
Could it be turned more In this type of build? I dont know, I was comfortable with these rpm and never hurt anything.
The motors I built that were larger (rpm-hp) had better parts. If you want to finish first you must first finish.
I am really amazed with the 5.9’s I’ve thrown some really cheap **** together and honestly didn’t think it would live 1 night and they always healed up well, good luck !!!!!!
1 more thing, Hughes has some really good articles about installing cams, making sure lifters rotate and such, he has a couple paragraphs about oiling and iirc it is in the stroker section, not his oiling section, kind of hard to find.
I know a lot of people have bad experiences with Dave but he really helped me out a lot on what works and what doesn’t!

 

[Dale Davies]

HI guys,

Please take kindly to the title as it's an attention grabber to get some of the old heads in here to help out.

I will clear the air before we get that one guy in here, my plan is to build a 73 Duster Multi purpose car that I can drive on the street/weekend/Road Race (laguna, sears point, willow) etc.

I want to do this from the ground up and instead of throwing in the Gen3 hemi I have right away, I want to do a budget build to R&D from the ground up using what Mother Mopar has already made. I will have a 6 speed TR6060 with a shortened 5th and 6th gear for the trans and then a 8 3/4 with 4.10 SureGrip. The car the engine will be in will be around 3000 lbs.

My "IDEA" is to get a stock 318-360 LA/Magnum and push the limits on her and really see what breaks and what doesn't, but before I go cowboy on this. I wanted to bring in the voices that have been doing this longer than I have to maybe guide my route on what would be the better base engine to work with.

What I want to do or had in mind was starting with a stock engine, running it and seeing what she does and then slowly mod the engine and track the progress for R&D. Eventually I would like to help others in this MOPAR world like most of you have done for me, but I figure what would be better than a ground up journal build tracking a base engine build.

Today everyone wants to go fast and we all have been guilty of throwing parts to go fast or say we make this and that number, but I wanted to take it back and maybe be someone who says "****, I did that with a stock bottom end 318 and this is what we did to survive or this is what we ran into."

So I know that I may not be the first to do this, but I really want the challenge of taking the high road and testing on the road, not on a dyno.

So I hope any advice would or guidance would help..



Right now I have access to a 69 318 which I believe made 230hp and 340tq or I could look into a bare block 340 or a magnum 318/360 from the yard.

I'd like to go the cheapest route as many people starting off here won't have the budget or knowledge to go any other route. Plus a lot of the information I grew up learning from y'all is stored WAY BACK in the archives of this website.


SO Here is to the budget builders...

Considering budget up front, run what you have, the 318. Now we all.know torque and power come easier with more cubes. That can be limited by class regs.
The TransAm 302 Chevs and Fords with their 3.00" strokes raced running to 9,000RPM but to pass or stay ahead could run to.9,500RPM. The destroked 340's at 304CID ran up to 9,500 but could be pushed to 10,000RPM. Pontiac ran destroked 400 engines but I have no idea what they reved to.
For the Boss 302 TransAm race connecting rods, special rods were available that were considerably stronger but heavier than the stout OEM rods. These were definately not what you could consider budget built engines. For the day, they were putting out about 475HP from 305CID engines. Competition regs gave carb throttle bore maximum diameter that boiled down to a special (read expensive) 820CFM? carb that could be purchased from the dealer parts dept. With todays better cam profiles technology and valve springs more power should be available.

 

[DionR]

Just a couple of comments, not arguing.

In my mind, these older pushrod V-8s are just better suited to lower-RPM torque due to their valvetrain.

NASCAR is still running pushrod motors, and Engine Masters did an 8K RPM SBC. I agree an OHC seems to make it easier, just saying that it isn't impossible to RPM a pushrod motor.

The stroke doesn't have as much to do with its ability to support high revs like smaller engines.

Longer stroke means higher piston speeds and slower rev's. So a longer stroke can necessitate even stronger parts and might not rev as freely.

Based on comments above, I doubt the difference between a 3.31 stroke 318/5.2 and a 3.58 stroke 360/5.9 make much difference. Just saying that stroke can play a part in the design.