Max engine RPM

I think the best way to spend your money is to look at your weakest link and build accordingly.

If you use a late model 5.0 block, get the stock rotating assembly rebuilt with new pistons, good rod bolts and a ballence job (external probably). Get a good standard volume oil pump and drive shaft and a double roller timing chain (I like rollmaster).

Now spend what ever is left on heads, intake and cam.

That will get you a cheap, powerful engine, but not bulletproof.

If you start out with a $1,800 Dart sportsman block, it does not make sense to skimp on your rotating assembly, and it would be a shame to put stock heads on it.

If you find a Mexican block, that just asks for a cheap stroker crank and better rods, otherwise it's the same as the late model.

A Ford Sportsman block ($900) deserves a forged rotating assembly, but I crossed it off my list because the Dart is only $900 more and is much, much stronger while alowing a 4.125" bore and room to grow.

If you go with the 351, making 400 hp is like falling off a log. The production blocks are as strong as a Ford Sportsman block. Cast 393 stroker cranks are strong and cheap, they use stock 351 rods with 302 pistons. There isn't a cheaper stroker out there (not including Chevy 383). With merely decent heads and a lumpy cam, 500hp should be atainable.

I need an 8.2" deck engine, otherwise I would get a 351 in an instant. I don't have the gear issues and light weight that you GT40 drivers have, but you can't beat the bang for the buck.

 

[Lynn Larsen]

Ian,

I agree with Rev's assessment, but I would add that if you come down to making the bottom line work and there is no wiggle room in your budget, I wouldn't hesitate to use a Ford R302 block if one comes along. Dart has the equivalent of this block now as well. (They have 4 bolt mains on 2-4 and 2 bolt caps on 1 & 5.) If I had to choose between the Ford and Dart, both being the same price, the edge would have to go to the Dart because of it priority oiling set up. You can do the same thing with the Ford, but you have to place restrictors in the passages carrying oil to the top end. ( I haven't mapped the oil gallies myself, but the way I understand it the Ford passages will, left to their own devices, tend to supply a disproportionate amount of oil to the top of the motor vs the bottom end.)

I agree with his statements on the balance. To take it another step though, if I were going with external balance, I would use 28 oz imbalance rather than the late model 50oz.

Lynn

 

[Gary Gibbs]

Lynn,
Last I looked at those lifters they were only made for SB Chevy. Someone is making pressure fed lifters for the actual bearings.

 

[Russ Noble]

So to explore the 351 scenario if you were to do a 351 with hyper or forged say 12 to 1 pistons and good bolts, crack tested and zero balanced (is zero balancing economically worthwhile with a budget bottom end?) running on race gas and big heads say 225's and a big manifold (because you ultimately want to be able to grow the motor). Engine revs are obviously able to be best limitted by a soft rev limitter but what sort of carb/cam setup would you choose for maximum power through the top half of the rev range bearing in mind the limitations imposed by the stock crank and rods? What power/revs would that be likely to be? I am not worried about low speed drivability issues and the motor would get a precautionary strip and cracktest annually which would probably be less than 2000 competition miles.

 

[Lynn Larsen]

Gary,

You are correct that Endure-X are listed for SB Chevy. The GEN III are used by some NASCAR teams in Ford blocks. I susspect you would need to call Comp on these and choose very carefully to get the proper lifter fully expecting some machine work to be needed on your lifter bores. However, there are models of the Endure-X which have the same diameter as SBFs use. Depending on the block you are using, they can be made to work as I have seen them used in Ford engines before. Caveat here is that one should have a good machinist/builder double checking not only the diameters of lifter, but also the diameter of the bore, oiling passage location and the height needed to clear the upper shoulder of the bore. These aren't for a buy it, install it and run it DIY operation. I think these can be purchased from FTI already prepared as I saw a guy from a South Carolina race team advertising a used set on one of the Mustang sites.

The more likely scenario would be to buy a set of Comp 838-16 solid roller lifters and cut an oil path down the side of the lifter body; thereby, making your own Endure-X lifters. I am thinking of getting a fine diamond point engraving tool for my dremel to create the groove. Again, this isn't rocket science. Of course, if one were to do this, one would need to make certain that any edge that might be lifted up higher than the lifters surface were smoothed back down to make a clean V cut for the oil path.

Next in terms of ease and economy, would be having a similar groove cut in the bore. This would take a bit more planning and precision to get the groove in the proper location. This would be determined by the width of the oiling rabbit cut around the middle of the lifter: probably not a DIY operation either. Lastly, a good machinist could disassemble the lifters and bore an oil path ala the HPPO option on the Crower lifters. Crower lifters with the HPPO <u>are</u> available for SBF though: 66215H is the part number.

Edit: Isky now has their Red-Zone lifters with a similar oiling scheme. Summit price is $606.69 for ISK-3972-RH.

Regards,
Lynn

 

For that engine, you probably want a pretty big cam.

If the short block is a stock style rebuild, I think a good limit would be 6,500 rpm. Plenty of 351's regularly see that RPM range, so it's probably safe if all of the machine work is good. The block is strong, the crank has large rod and main journals, so it is a strong piece. The rods are probably the weak link, but they are strong also.

Since the crank shaft has larger diameter counterweights, the ballence job should be easier than a 302. Eagle is suposed to be real close to their target bob weight of their cranks. You can use that weight and the actual bob weight of the parts you want to use, do some math and see how much you will need to do to get zero ballence. Take that number to your crank ballencer and ask if they can do it.

If you are building the engine for competition, I don't think it makes sense to skimp. If you are not competitive, the little devil wispering in to your ear will say "we don't need any rev limiter".

You might get away with 7,500 rpm for a while, but if your oil system isn't top notch, you might go dry in a corner.

So, if you spend the money on all of the good parts, a forged bottom end, dry sump oiling, race block and big heads, you will be rewarded with a 7,500 rpm engine that is fairly reliable if you follow a strict replacement plan for high wear parts, and probably 700+ hp.

Making power is the easy part, you just need good heads, good intake and a big cam. Reliability is expensive.

For the carb, a demon carb is good, but I don't know if you can get them down there. Holley makes a high performance version without a choke, that might be good. I'm more of an EFI guy.

 

[Russ Noble]

Thanks for the good info Built2rev,I can live with a 6500 limit in the mean time. The important thing is to get the car built, running and sorted as soon as possible,then a spraybar cooling system on the transaxle, then a fully forged alloy block 4xx.If I were to do all this first, the sheer expense would delay completion by a couple of years. I know what you're saying about switching the limitter off. Been there done that with my TR7V8! The damage that caused earlier this year was one of the deciding factors in the decision to build a GT40.

I must say this is a most informative thread as are many on this site.The support and depth of expertise from other knowledgable enthusiasts is awesome.

Regards.

 

[Lynn Larsen]

FYI:

With a little shopping around, I have been able to find Crower HPPO solid roller lifters and Isky Red-Zone lifters for $460-$475 price range. Check out Car Shop Inc. They have some really good pricing; I talked with Tim.

I have not been able to talk with anyone who has used the Isky Red-Zone lifters. If anyone knows someone, or knows someone who knows someone who has used them, I'd really like to find out how they have worked for them.

That said, I just talked with Charlie Long, the NASCAR engine builder, and Crower HPPO are considered the gold standard to them. Those that can afford them will step up to the Jesel lifters, he said. While they like and use lifters with pressure oiling to the roller bearings for insurance, in general terms he used the same example that I did earlier of the dry sump racinging engines where they are pulling significant vacuum on the crankcase to get every drop of oil out of there that they can and don't feel it is necessary to provide any extra oiling to the roller/cam interface beyond what the pin oiling and other sources provide already.

Regards,
Lynn

 

[Gary Gibbs]

Nice info from Charlie Long. keep in mind that a NASCAR engine is designed to live at high RPM for 500+ miles. The requirements could be different for an engine that is going to spend a lot of time in the low RPM range, etc.