[1968HemiDart]

I’m currently rebuilding my 5.7 Hemi bottom end with stock crank, rods, and pistons, although it has clevite P bearings and the rings will be gapped for a small shot of nitrous. The top end will be ‘13 eagle heads with a big custom ground Hughes engines camshaft, and a Ritter racing drag pack style intake manifold. Knowing the engine should make over 500 flywheel horsepower, I’m starting to think I can’t put a small shot of nitrous on it since I’m feeling like I’ll already be close to the limit of the stock pistons and rods. Can anyone tell me if this will survive a 100-200 shot?

 

[DBL.DWN]

I think that'll be pushing it. I would drop a forged rotating assembly in. I saw your other post about the cam. I for sure would not flycut the stock pistons then run the nitrous on top.

 

[chrisp2493]

How are you planning on getting 500 hp from a heads/cam 5.7? That seems like a stretch

 

[1968HemiDart]

Yeah if I have to flycut the pistons I definitely won’t spray the motor also, and I’m saying 500 because it’s going to be a high compression motor with ported eagle heads, and a big cam. The newer eagle heads respond extremely well to these kind of modifications since they are significantly better than the 03-08 heads

 

[DBL.DWN]

Other thread you said 0.075" head gasket. What compression ratio you going for? Nitrous loves compression and with a large cam bleeding compression off, you will probably want to bump it up.

 

[1968HemiDart]

My eagle heads are getting milled so along with that 0.075” gasket I’ll have around 11.5:1 I’m aiming for the edge of 93 octane pump gas.

 

[Newoldchallenger]

My build is fairly close to yours...minus any adjustments you have in rebuild. Is it an eagle 5.7 block or non?
I run a dual plane intake manifold (OCPerformance), a 270 comp cam (pretty sizable on the 5.7), and ported eagle heads (and lots of other stuff). Then a 100shot from a NX gemini plate system. It makes about 500rwhp and 550rwtq. Over 40 drag passes and some street testing, about 30 bottles through it and it's still going strong.
I think a 100shot with the correct plugs and afr will live on your build for a while.

Sent from my iPhone using Tapatalk

 

[ChuckWagon]

You can run 13:1 on 93 pump gas...been doing it for over 140,000 miles now

 

[1968HemiDart]

I’m running an non eagle 04 block, and @chuckwagon have you driven that thing around with no overheating? Also what kind of timing do you run for 93 octane with that compression?

 

[DBL.DWN]

Cam selection will really determine how much static compression you can run. Thats what I meant hen saying the large cam could bleed off compression.
Static 13:1 would be great for nitrous.

 

[chrisp2493]

I think it would be a great idea to look into some forged parts. Pick up a used 6.1 stock crank, and some other rods and pistons. If you are building it for a cam good for 7k, high compression and nitrous on top of it, you’re just flirting with disaster.

 

[ChuckWagon]

I'm running an non eagle 04 block, and @chuckwagon have you driven that thing around with no overheating? Also what kind of timing do you run for 93 octane with that compression?

No overheating here. Guy that built my car put an "export" radiator in it...which I think is a radiator that goes in a car meant for overseas hot climates....I think.
I currently have a 180° thermostat in it and even have a 160° that I run sometimes.

Timing? I'd have to look at the tune but I don't think it's extreme. I'm 116 LSA though and I know a buddy of mine had a 112 and had all kinds of trouble tuning it...but..it could've been his guy doing the tuning that didn't have the skill to get it to run.

One thing though with high compression, run 93 octane fuel for a while and then throw in some 100 octane or MS109 and hang on as there is a noticeable bump in power

 

[Newoldchallenger]

I really don’t think 500hp is the limit on the old blocks but that’s my opinion. Lots of the ram guys threw a **** ton of nitrous at their old blocks for years. Lx guys built more than 500hp cars on non-eagle blocks.
I would make sure the cam is a good match for the juice and make sure that it is tuned conservatively (afr wise).
Interested...is this going to be a carb car? Is it an old school swap? Racing?


Sent from my iPhone using Tapatalk

 

[formerice]

Weak link isn't the block, it's the stock cast pistons. As long as it's tuned so that you never get detonation. you'll be fine. By increasing the ring gap on the top ring, you are much safer imho. I would still not go over a 150 shot.

 

[ric3xrt]

I have one Question, are your "stock " pistons, OEM Mahle or one of the aftermarket stock Cast piston? there are two major issues with the Mahle as run 03-08 factory pistons , 1) the top ring land was too close to the top of the piston, which they changed for the 09 and later 5.7s, the other issue was the stock ring gap was too tight , something in the .008-010 range, considering the location of the top ringland , DHJ and Enginetech after market pistons have the top ring land down where the 09+ 5.7s have them.the Guys I bought my Solar Yellow 05 GTxtreme from had rebuilt the stock 5.7 with Enginetech pistons, stock 5.7 crank and reworked stock 5.7 rods from the org 5.7 engine. Gaped the top rings at .018 ran an Arrington NOS Throttle body, they ran the truck with both a 150 and a 250 jet, ,Howards Camshaft 786045-14; .600/.600" and stockish Eagle heads and Jeep intake manifold, with a MSD window switch set at 4800 , When I bought the truck the rebuild had 35k on it, pulled it apart and you could see the rod bearing were hammered on bad, I think 100/150 shot only would have been the safer bet , but the Engintech cheapies pistons held up well. 3 of the stock rods had a slight bow in them, which was only visible when all 8 rods were laying on top of each other, personally I think in another 5k one of the rods would of given up, again I think if it was limited to a 100/150 shot it would be fine.truck ran in the 11.20s range with the 150 shot and 10.50s with the 250 [email protected] 4550 race weight on my buddy Vince's mustang chassis dyno it had an average of 495/565 HP/TQ with a 727 trans behind it. ...now keep in mind that this truck had the AC deleted and ran an electric water pump. Alternator and power steering/hydro boost pump where the only assecories :::::::::::::::::::::::::::::::::::::: (9/14) just realized my typo in the HP/TQ Numbers should be 495/515 , Not 565 my apologies for the typo also the Jeep Intake manifold on this engine was the custom SRT8 Intake from America's most wanted 4x4 , it was not the stock jeep intake..

 

[DBL.DWN]

Great feedback. I was wondering how those enginetech pistons would be for a stock rebuild. I know their gaskets are pretty decent.

 

[Root66]

I admit to being old school but the term "powdered metal connecting rods" says no nitrous for me.