5.7 Gen3 hemi piston to valve

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rebelrouser
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5.7 Gen3 hemi piston to valve

Post by rebelrouser »

Have not messed much with performance on the early Gen 3 hemi. Does anyone have experience with how much lift the stock pistons will accept? I read that they have less than the newer engines. The engine in question is a 2004 5.7 out of a truck, so it doesn't have the cylinder kill system. best I could find stock camshaft is .472 intake and .460 exhaust, with 260/268 advertised duration. reason I am asking is I have a personal project, bought a 1965 Dodge Coronet convertible and going to install a gen3 hemi in it. I came across a low mileage Jasper reman engine out of a wrecked Durango. So, I am assuming the valve seats in the heads have been addressed. Just want to pop in a mild cam. Not going to run a computer injection, Indy modman and dual afb carbs for the nostalgia look. Most stage 1 cams are over .520 lift
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Re: 5.7 Gen3 hemi piston to valve

Post by BillK »

Not sure on the answer to your question but wanted to tell you to make sure you pay close attention to the head gaskets. One of my customers had the heads off a Jasper reman 5.7 Hemi and it had really thick head gaskets on it to make up for milling a bunch off the heads. I think they were in the neighborhood of .120 thick. The only place we could get the gaskets was from Jasper directly. They do other strange things like that to save blocks and heads so just be careful with parts.

Not real sure I would want to base a performance engine off that one. Maybe just put it in as it is.
Bill Koustenis
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6.50camaro
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Re: 5.7 Gen3 hemi piston to valve

Post by 6.50camaro »

I have a few EngineMaster magazines stashed away from the early 2000's when I still bought mags. I remembered they had one with a Gen III hemi.
Summer 2008 volume11 no.2 They used a XV Motorsports kit. It had a Comp Cams XFI 273 cam 273/277 adv. 224/228@.050 .547/.550 lift cam. Other than installing comp behive springs made no mention of having piston to valve clearance problems. This cam was used with a 4 barrel single plane intake and a 650cfm carb. Peak torque was 390@5200 rpm and peak HP was 438@ 6700 rpm . Good luck Dan
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Re: 5.7 Gen3 hemi piston to valve

Post by Walter R. Malik »

"Variable Valve Timing" or not will make a major difference.
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rebelrouser
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Re: 5.7 Gen3 hemi piston to valve

Post by rebelrouser »

2004 non variable valve timing engine
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Re: 5.7 Gen3 hemi piston to valve

Post by BillK »

rr,
I talked to one of my customers that pretty much does nothing but Hemis. He said that .550 is no problem at all and probably more. He suggested looking at the offerings on MMX for example.
https://www.modernmusclextreme.com/

I took a quick look and found this:
https://www.modernmusclextreme.com/p-10 ... shaft.aspx

By the way if the engine still has the Jasper tag on it you can call them and make sure there are no "crazy" parts involved. Pretty sure thats how we found the head gaskets I mentioned earlier.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

www.enginerepairshop.com
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