new motor build questions

With blower motors (roots 14-71) is there a huge benefit to the latest and greatest heads. Ie new brad ta1x or new noonan/MBE stuff versus older stuff like brad 5 or 6'? Or is that just what makes the motor a few hundreds of a second better than others and really its all blower? tune ? cam ?

How about ideal bore stroke ? 4.5 bore small stroke ideal ?

any other comments feel free to add thoughts.

 

I would say that the 2” lifter spread on the block will be worth more than the latest and greatest heads, depending what your trying to do. All the latest heads are similar, never ran brads but the AJPE stuff is nice, but I prefer the Noonan stuff. If your trying to run NHRA or PDRA with a blower/turbo you really need a 4.9 Noonan or AJPE to keep up, maybe brad makes one too? If your trying to go to your local series and qualify, a brad 6 will most likely accomplish that; depends on what your goals are and how big your budget is.

 

Guess nobody knows anything in this forum except for you rb0804.
Nitrous and motor forum would have 200 opinions - lol.

Thanks for the reply.

 

Plenty of great knowledge in this forum for sure. You won't get 200 opinions here, just a few good solid ones you can bank on. rb0804 is definitely proof of this. His response is pretty much spot on. Really depends on what your plans and budget are. You are obviously talking hemi, and there are a lot of good options as far as heads go. My buddy runs an older KB cast block with brad 5s 3spd lenco. Gone 5.94@ 245 TAFC on a mediocre track. Good track maybe 5.7s 250+. And that setup has been put through the wringer. Only turning 9500 rpm. It's a d rotor though not a roots. A resourceful guy could probably duplicate that motor for around 30-35k. You can easily get 20k into a set of latest greatest heads. Noonan, AJPE, BAE older stuff is more affordable and won't really be the limiting factor in your quest for horsepower and speed. It's definitely not like using an old set of Brodix/Dart heads vs the latest Head Hunter chevy stuff.
I think you're already on the right track thinking money can be better spent on blower setup, cam/rocker arms/valvetrain, transmission, converter/clutch and proper tuning. Especially if you're just looking to haul ass and compete locally and not win the big show nhra championship.

 

If you're trying to be at the front of the pack everything matters. Don't get caught up in the "got to have it syndrome" to run very well. We ran 5.50's back in 04 with a set of dual plug brad 5's on a d rotor TAFC. Make your combo happy and efficient .

 

If it was me and I was looking at trade off because I didn't have the budget for all top of the line components. I would spend the money on the fuel system, blower, hat, etc. I've seen good fuel and blower set ups run well on not so great long blocks. I've seen top of line long blocks that ended up with lesser fuel and blower packages because funding ran out that didn't run so well. With the roots stuff that's not a place where you can skimp. I'm not saying you need to sign up for a lease program but do buy as good of equipment as you can in that department. My 2 cents anyway.

 

Try and stay as current of a setup as possible. Then you have access to off the shelf parts and quality used stuff. When buying outdated engines finding Quality used parts for spares becomes a real challenge. Then you’ll kick yourself in the ass for taking that road. Truth is you can buy used legal roots engines that are tried and true for pennies in the dollar. Most those guys are moving to the 4.900 Noonan stuff.

 

Just a couple other things to touch on:


If you go 4.500 bore you have to keep on top of it. 4.5 bore in a 4.8 bore space block is a little sketchy. Lots of guys run the 4.467 as it’s pretty durable. If you go big bore short stroke, your gonna have to RPM it, so you will have to keep on top of your springs also.


If the block and heads are not oring’d around the oil feed hole in the deck, it’s a good idea to go ahead and Oring it.


Camshaft: for the most part a cams a cam, they all make about the same horsepower but they tend to move it up or down in the power band. Some cams are more valvetrain friendly than others. The 296/296 .500 is the “standard” cam.


Rocker gear: anything that oils the pushrods is ideal, eliminates a lot of ass pain on pushrod tip issues. Still Lube pushrods at the start of the day, everyday.



The tricky thing with the hemi used parts market is you have to do your research as there is tons of aftermarket stuff out there. You have Noonan, Brad, AJPE, MBE, CoLine, VENEY, MBR, Frankenstein, etc. Not all the parts and pieces interchange. Know what your getting into and which parts fit each head. Also take into account your geographic location vs. your engine of choice. If you hurt your stuff and have to send it back for repair, how long is shipping going to take and how expensive is it going to be? Shipping stuff from the east coast back to the west coast and vice versa can be a pain at times.


To touch on the nitrous comment, you may get 200 replies, but how many of them are legit? My experience with nitrous guys is they all go off of what their buddy who knows more than them told them and he learned that from someone that went fast one time 20 years ago. I have been working with a clutch program on a nitrous car and we were able to pick it up a good bit by breaking some of those old time nitrous ‘rules’ or whatever you’d like to call them.

 

Ask as you shall receive. Lol

Thanks guys.

 

Most guys are running the std 4.8 Billes has done well with the 4.9 in pro boost PDRA. Unlimited funding as well. TA1X is what I would use.

 

Curious why you feel 2" spread bore is worth more. thanks

 

Lifter geometry gets fixed. Major improvement.

 

Major improvement is an understatement. The 2.200” lifter spread is even better and I believe they go wider than that. There is a lot of heart ache and broken parts that come with the Hemi and RPM. Anytime you can make your valvetrain more reliable and easier on parts I’ll take that any day of the week over something like a new set of heads that’ll give you 100 hp. Cause guess what? With the better geometry you can pick that back up down the road with camshaft design and/or RPM. At the end of the day RPM is king, there is a reason why a lot of classes have an RPM cap. That’s my two cents anyways.

 

Hey Rob, can you expand on why? That's only about 16 thou wall thickness either side. Hey for giggles, how about a 4.500" bore and a 3.570" stroke, big RPM, C-Screw That would be a true ""454SS"" big block. Thx.

 

The pushrod holes in the gasket are close to the sleeve. Guess where a hemi usually torches the head or has a gasket failure? Also you are about maxed out at 4.500 on a 4.8 bore Center. If you don’t have a spread lifter bore the pushrod deflects and rubs all up into the sleeve and gasket area also. The Chevrolet (includes the 481x) is on a 4.84 bore Center, as is the Arais/Fontana/MBR thing, which gives you a little bit more of a cylinder wall thickness, and cylinder rigidity at 4.500. With some of the 481x stuff we were going 4.560.

So in short, it puts you closer to the pushrod hole, your cylinder wall thickness is less and now your also making more power. All these things shorten the life of the parts so you just have to keep on top of cylinder trueness, ring seal, and make sure you don’t make a tuneup mistake that will cost ya a blown head gasket. So you just have to “keep on top of things” and may not be how someone who races top sportsman, grudge, or local promod stuff would like to race. How about we go with an iron block and go with a 4.600” bore and a 3.50 stroke? Still be legal for TAD. Good luck making minimum weight.

Just some thoughts on sleeves: The steel liner in an aluminum block isn’t really ideal. It’s nice to have the weight savings of aluminum with the flexibility to repair it at the track. Scorch a piston and a sleeve? Just bang one out, bang one in and your ready to roll. So let’s look at what’s really going on. A steel sleeve doesn’t expand at the same rate as the block. It also sticks out a little proud on the deck surface a few thou. How much depends on who’s block you have and how hard it was run before you got it. This is done to get a good head gasket seal (back to they expand at different rates). So basically the sleeve is “captured” at the top and bottom which leads to ballooning in the center and loss of ring seal and blow by. Thicker sleeves and billet blocks have helped this issue tremendously, but as always there is always room for improvement.

 

THX Rob. I love it when you remind me how much I dislike pushrods. Have a good night.