D9HP

All,

New here - read quite a bit but have a few questions.

I'm building a 1975 Mercedes Benz 450SLC AMG Mampe-inspired road racing/autocross car. I am hoping for the finished package to be around 2800lbs dry and 550RWHP with a C4 Dana 44 rear end running 3.44-3.70ish gearing (depends on transmission setup). No desires to ever run any power adders on this car or this engine. Permanently N/A.

This isn't a two week (or even two years ) project but I am starting the engine now.

I am planning on an LS3 based build here shortly by buying a brand new LS3 block and having it bored and honed locally to 4.080" and running a 4.1" K1 crankshaft for just over 427ci. Wiseco pistons and K1 rods. I know that criticism of the 4.1" stroke abounds but I've seen quite a bit of success for N/A engines.

ARP hardware for any bolt I can get from them.

Still deciding on heads. Love the idea of Mast Motorsports but not sure if the cost is worth it compared to the Trickflows. Comments here welcomed!

Planning on using a used LS3 intake, injectors, ignition coils, front and rear covers, any other non-wear items I can find.

I am still wrapping my head around some of the camshaft choices I've seen and would LOVE some recommendations here. Will be going through Comp cams due to previous experience with the company and their service.

It will not be a daily driver and will be towed to VIR for track days whenever I have the weekend off and the time. I also will take it to the mountains of NC a few times a year for more relaxed cruising on the blue ridge parkway and a bit more spirited drives on a few other more rural roads. This will never be a comfortable car so I am willing to sacrifice 95% of it's drive-ability and have a high idle for more mid to high range HP. I don't think I'll need more torque out of a stroked 427...

Planning on a Holley HP EFI system for the brains behind the whole jam.


Major questions:

1. Do the 4.1" crank and K1 rods introduce any clearance issues or is it typically a drop in ordeal? Just budgeting my time at the machine shop since they will not be doing assembly, just balancing.

2. For a totally N/A engine using the new Wiseco piston design are there any substantiated criticisms of the 4.1" stroke?

3. Best heads currently available for <$1000 each bare? I love the Mast but the price tag is a bit of a shocker right now.

4. Cam suggestions for a high-cube road racing engine?

Much appreciate the time, folks.

DietCoke

iTrader: (18)

1: Yes, you have to do a lot of machine work so they clear.

2: Yes, but it's better then the 4.125 stroke. If you're going to road race the car or run sustained RPMs, go with a 4" stroke crank. There is also little reason to bore it to 4.08, because you are at the block limit at that point.

3: TSP Small LS7 heads... but they require ls7 hardware.

4: You're going to need some sort of serious crank evac/breather system on an ls3 stroker, windage is a major issue. Plan on at least a pair of -10 breathers from the valve covers to a tank, or a vac pump.

427zm

iTrader: (9)

First things First listen to Diet here. He already has a 430 ci LS3 stroker.

Couple of questions for you OP:
1) why not consider a resleeving your LS3 block though ERL (http://www.erlperformance.com/gm-ls-...e-short-blocks) or R.E.D. (http://www.raceenginedevelopment.com...4927/index.htm). Both can set you up with a 4.125" bore or greater motor and you will find better durability from the package IMO. I currently am having an LS2 based 434 (4.155" bore x4.0" crank) built by ERL and will do the occasional track day with it.

2) being that durability is going to be key, why not go with a 3.90" crank? It'd slow piston speed down, as well as piston rocking.
3) as for heads, PRC's LS7 based heads would be a good setup as would Mast. Both as more expensive than you're interested in, but with this kind of build, good heads are imperative. You could find stock LS7's for near 1k, but you'd need to replace exhaust valves and guides immediately. While doing this, you'd want to port them as well. Cost will near the PRC's with the acquisition of the heads porting, so PRC's may be best.
4) as for cam, the Katech K501, or Torquer 110 would be my first suggestions. Both have the road racer in mind. Past, that, get with Martin@tick, Pat G, or another head/cam guru to set you up.

DietCoke

iTrader: (18)

The heads I mentioned can be had for less then 1000 bare. The valves are where you spend your $$... and Ti valves arent cheap, but pay dividends in valvetrain stability

427zm

iTrader: (9)

Amen. TI's are the best you can buy, and I do it for you building a purpose built road race motor.

D9HP

I assume it's the same for the 4" stroke here?


EDIT: Just saw that YOU have a 430 stroker. I'm leaving this as I wrote it but definitely will want to read through some of your post history. Makes sense to steer away if you're advising it's not a wise choice.

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First, I really appreciate the response and I definitely don't want to come across rude - but is the main reason for not liking the 4.1" stroke mainly just being conservative? I've read a handful of success stories and have only found two comments about excessive oil consumption and it pre-dated the newer piston designs.

I hear a lot of people advising people against a 4.1" stroke but I don't see many first-hand accounts of death and destruction or serious issues.

Also, road racing is probably the wrong term as I will be mainly just taking it to the track for a handful of hot laps with a local club. It will never be a competitive vehicle or anything like that.

As for the bore - good point. Might want to give myself room to hone it later down the road.

It comes at 4.065" (unfinished) and it seems like Wiseco has 4.070" pistons off the shelf with the configuration I want for a stroker build. Is 4.070" reasonable?



So the LS7 heads with a much smaller bore are not a big deal?


Just a line from each valve cover to a vented catch can? I've read a few things about this and am aware of blow-by due to my lengthy experience with older diesels.

Again, thanks for the input.

D9HP

Will do. Really have been interested in finding people with direct experience on this.

I have not purchased anything yet so I am wide open to my options and certainly want to see what I've got.

I don't want to spend the added $2k on the sleeving process for a displacement bump since I don't really have any particular numbers in mind other than 500+BHP, which could honestly be had far cheaper than I am even doing it.


Durability will be key, indeed. I'm not opposed to the 3.9" crank at all, either. What's the max stroke I can run (using stroker clearanced rods) and not have any clearance issues during the installation?

Durability in mind - also note that this engine will likely see well under 1k miles annually. It will be a totally stripped down car that I might occasionally drive to work on sunny days if I want to smell like gasoline on a half day.

Right, I want to buy new heads. That's where the really big horsepower numbers come out of these engines from what I've seen. I only want to do it once so I'll pay the high price tag if I have to.

Will check into these and ping one of those guys once I sort out my finalized displacement and bottom end.

I really appreciate the input.

So the high dollar TI vales are worth it? Just from a strength standpoint?

Thanks guys.

DietCoke

iTrader: (18)

4.07 bore is a good starting point because it lets you get a good line hone on the cyls and still have a useful .015 to play with if you need to hone or bore in the future. The issue with the larger stroke is piston skirt wear - not catastrophic failure. It just won't live long because it ovals the cylinders and wears the skirts due to piston rock. I don't expect to get more then 10-15k miles on my current motor before it has to be gone through and honed/new pistons. Just the nature of the build. a 4" stroke will last forever. If you're road racing, the wear is exponential because of RPM. Just think about it - HP is the same with a 4 or 4.1 stroke, you just make it at different rpm. If I were to do it all again I'd go with the 4" stroke (and my car makes some power).

The LS7 small heads are fine - it's just an ls7 port with a smaller exhaust valve, but the benefit is you use the superior ls7 rocker geometry, and better ls7 intake port and intake manifold.

Ti valves aren't stronger then steel valves. Valve strength is a non-issue. Ti valves are much much lighter the steel valves, which adds to valvetrain stability (ability to make power at high rpm) and durability, because everything in your valvetrain doesn't have to work as hard. The stability/durability/rpm potential of Ti valves is why they should be used.


A -10an (5/8) line from each valve cover to a catch tank would work. You can also run that line to your headers and do a header evac. I have a vac pump on my car. More then one way to skin a cat, the real key here is just having enough ventilation.

D9HP

The Torquer 110 has a pretty desirable curve - really love that smooth torque.


Great. Will go with 4.070" Wiseco pistons and save the trouble of a custom bore size.

Wow - I was aware there would be a bit more lower skirt wearing but not within 10k miles.

Good to know! 4" stroke it is.


So that .1" in the stroke is really that big of a difference?! Color me convinced.

And yes, you're making serious power. I looked through some of your videos and I think the weight reduction in your Camaro is even more impressive.

Okay - got it.

There doesn't appear to be much of a benefit to running a Fast intake for the LS3 style heads but would it be worth while to run something like that with the LS7 heads? I haven't looked into any LS7 stuff as I didn't have any plans on running it.

All things equal otherwise would I see a notable difference in HP going from the LS3 block (4.070") to the LS7 block (4.125")? (416ci vs. 427ci)

Makes me wonder if the additional block cost would warrant it (+$1200). Jegs has the LS7 block and it says it's finished at 4.125" so it would reduce my machine shop costs some as well.




Okay - awesome.

Again - I appreciate the help!

Gray86hatch

iTrader: (83)

Price everything out the ERL using a $250 5.3 block vs a $1200 Ls3 plus machine work it is not as far apart as you think

Tim

DietCoke

iTrader: (18)

The Ls7 block will probably net 10-15hp due to larger bore (less valve shrouding) and far superior bay to bay breathing. It also has billet main caps, which is a nice strength piece. Worth $1200? Eh.

Like the guy above me said, you can probably sleeve a $150 5.3 block and have better results for ls7 money.

D9HP

Where can I find a $250 5.3L aluminum block?!

And where can I find a $1200 LS3 block?!

I haven't seen prices like that anywhere.

The ERL website shows $2250 for the sleeve services plus another $1300 for the LS3 block itself. Seems like the additional horsepower and stroke would not be worth that additional cost based on HP/$.

DietCoke

iTrader: (18)

The junkyard!

D9HP

About what I thought. Not worth the added cost to me.

Ah - I didn't have any luck with dead LS1s and other aluminum blocks in my area when I first started looking at used engine packages. I do not have very much flexibility during the week with my job so the new block shipped to my door is likely worth the convenience.

Seems like a 4.070" bored 4" stroke LS3 is in my future. With an aggressive cam (like the Torquer 110 or even more lift) and Mast LS3 or TSP LS7 heads (shooting for 11:1 CR for 93 octane pump gas) what sort of crank HP figures should I be expecting?

Assume a custom cold air intake system, large throttle body and 2" primary long tube headers.

Can I realistically get this thing in the 640-660HP range? Honestly, anything over 600HP at the crank is likely going to be tons of go for this light car.

427zm

iTrader: (9)

Resleeving a 5.3 is the way to go cost wise,and as mentioned above, by the time it's all said and done, you'd be talking less than 1k difference. I know, b/c I was were you are now 6 months ago. For a 5.3, resleeve talk to Steve Demirijian at R.E.D.. If he still has a couple, you can buy a fresh aluminum 5.3 block for $500. Sleeving it with a 4.125/4.155/4.185 bore sleeve out the door is like 2k IIRC. Your rotating group, and finish machining work and installation would then be on you to get done locally or do yourself. I figured when I was going through it, cost for the Shortblock this way was roughy $6k shipped and ready for heads. When you start adding up a LS3 done the same way, your cost wind just $700 cheaper. That extra $700 is well worth the extra power and torque you can create with the bigger bore IMO, hence why I went with the 4.155 bore x 4 stroke LS2 ERL motor.

Ultimately, I found an LS2 block for $500, and sent it in after ERL started my build. They honored it as a core, which saved me the $1300 core charge they have on their builds. This puts my overall cost of the build at ~ 6k plus shipping it to me. Tough to beat IMO for the power and durability it'll have. An all forged package that I'll be running LS7 heads with! I believe I'm going to run the K501 cam and should put out near 600 wheel. For your scenario, with a torquer 110, and detuned a bit, 550 all day long with torque from idle all the way up! It's a nice setup.

My advice is to call Sean or Seth at ERL and also Steve Demirjian at. R.E.D. and discuss your thoughts with them. Both shops are great to deal with and are a wealth of knowledge. For me, Seth and Sean talked me out of a stock sleeved built LS3 stroker. The small difference in price is extra durability in the long run.

I've done the research, but I encourage you to talk with both groups and figure out which way you want to go.

D9HP

Okay, now you have my attention. With the sleeving isn't it also possible to run the 4.1" stroke as they have a deeper cylinder? $2k for a 427-454 block is incredible.

A 450ci aluminum small block rotating assembly for $6k seems pretty damned remarkable. (4.185" bore with 4.1" stroke)

K501 cam looked like a great compromise with unreal high RPM power from those curves.

Sounds like you're going to have one wicked drive, man.

Yeah, seems like if I can be patient and find a used bare LS2 block locally I might end up on the top side by having the block sleeved and running a larger bore.

Would love to know the thoughts on the longer 4.1" stroke with an ERL sleeved block, for example.

Cheers,
D

JakeFusion

iTrader: (7)

Plus with a resleeved block, you can go with a much longer crankshaft, since the sleeves are longer and eliminate the rocking issue.

However, with a road race car, I would not overstroke. Bore is your friend. Not stroke. RPMs put a lot of stress on larger strokes due to the increased piston speed. If you want it to hold together, I'd stick with a 4" stroke and do a 4.155" bore ERL or RED resleeved 5.3L block from the junkyard. 434. You can do a 4.125" stroke and 4.185" for a 454 tho, and it would be really awesome... for the same exact price.

I'd also recommend LS7 heads over anything else available for the Gen III/IV. The TSP heads with either the hollow-stem intake or Ti valves is what you want. Or contact Richard @ WCCH and get the All-Pro LS7 heads.

Gray86hatch

iTrader: (83)

The ERL is ready to assemble. I did a 418 ran it for 2 years sold it for my 454.

I paid almost $700 to have my 418 bore hone deck and mains.

The sleeves are better for even a 4" stroke

Tim

D9HP

Right on the bore - it would probably be better to even go with a 3.9" stroke for the track but honestly, I've always wanted to have a gnarly stroker V8.
That 434 idea is pretty inviting though. A 4" stroke really does seem like the best option but then you have to go and throw out the big 454 number and then my mind reaaaally starts going wild. A 4.185" bore at 4" stroke is a 440 - that's also a pretty sweet number! Seems like I'd make gobs more torque with a 440 vs. a 416. Enough to warrant the additional work to make it happen, for sure.

And like you say...same damn price! 4" stroke it is though, whether I go with a brand new LS3 block or this new sleeved option.

So I don't think I have looked into the 5.3L block much. What's the letter/number code for that engine? Is it really that easy to find? It's not an LS engine, right?

Is everything else going to be otherwise the same going with that block after sleeving?

Right, seems like it's a very cost effective way to have a bulletproof stroker block!

Have a thread on that ERL 454?

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So even if I do the LS3 4.070" bore it sounds like I should do the LS7 heads. Is that the case for Mast Motorsports LS3 vs. LS7 heads?

Gray86hatch

iTrader: (83)

No I don't have a thread. I didn't have time to stop and take pics. I was behind schedule with getting ready for dragweek