Help me rebuild my 1978 350 5.7

[boatman37]

First off, ease up on the condescending attitude! as i said, go with a stock pump or if you want a high pressure but no high volume. i do not understand the internals of an oil pump but do understand engines and clearances. this advice was all taught to me by NHRA and IHRA champion engine builders. and i know for a fact that a HV pump takes more power to spin than a high pressure or stock. enough to notice by the seat of your pants? probably not. i have seen oil pump shafts snap and have seen 2 drills burn up trying to prime HV pumps. these were on race motors, not stockers i have never seen a pan sucked dry by a HV pump but have been warned about it by builders much more experienced than i was and they built serious power. also the main reason for larger volume oil pans.

for what the OP i building a stock pump is fine, as I said initially. i added that if he wanted more pressure to avoid a HV pump and either buy a high pressure pump or add the washer in front of the spring, but that was optional. some people refuse to run a stock pump and automatically think they need to buy a HV pump. i was throwing that out there as an option if they didn't want a stock pump. long ago i worked in an auto parts store and more times than not when a customer wanted an oil pump they opted for the HV. i asked why and they said they didn't like <10psi at idle as it made them nervous. with a stock pump and washer in the spring i would usually be around 20psi at idle hot. these were all with fresh motors with clearances on the tighter side of the acceptable range.

sorry to the OP for this being turned into a p***ing contest but just giving you my experience from several years of engine building. on that note i will bow out of this thread since obviously i know nothing

 

[dohcdelsol93]

Wow....well...i plan on this being a build for longevity. If i wanna go fast i have a y flyer 18 (a scow racing sailboat for the non sailboat crowd)

I want to improve horse power (more torque) without sacrificing the longitivity of the alpha 1. I will continue to look for a bravo outdrive and closed loop cooling but only after i find a boat that has had a tree fall across her and i can buy everything for a song.

I had planned on having the motor out by now but life keeps getting in the way and paid projects (that help fund this rebuild) keep coming in.

Did anyone here tell me exactly what cam i should use in my older 5.7 block? I kept getting roller cam recommendations.

 

[Bondo]

.i plan on this being a build for longevity.

Ayuh,.... Then you should scrap or sell the original motor, 'n update to a motor built after 1986, or better yet, after 1996,....

That way you can have a roller cam, 'n after '96, the roller cam, 'n Vortec heads,....

The '78 is really antique technology,...

 

[dohcdelsol93]

My god...what is with the anti pre 85 crap...i have a surplus of old 350 blocks. Please tell me how much hp and fuel efficiency i would gain by switching to a vortec block?

I am using one of my pre 1980s 4 bolt mains
Standard oil pump
96 model vortec heads (already serviced and ready to slap on)

What cam should i use? Will not be upgrading to behive springs or machining for more lift.

Target goal is 300 hp.

Among the auto crowd, a stock 350(pre 85) with vortec heads and heads only, (stock 350 cam and pistons) is good for 30 to 40 hp.

My stock block is rated for 260. Im hoping with a slightly hotter than stock cam and the better flowing heads 275-300 is easily obtainable.

I just need that flat tappet cam recommendation

 

[alldodge]

I would suggest calling Crane cams and ask them to recommend one
http://www.cranecams.com/contactus.php

 

[scoflaw]

Flat tappet cams are so outdated. You can get a much better cam profile with a roller

 

[dohcdelsol93]

I will make a call to crane. Its too bad the new ls engines take so much money to run in our boats. I keep running into the 5.3 ls engines for next to nothing.

Programming, exhaust, closed cooling system. Would cost 5k to run a 500 buck engine.

I should have already had my motor pulled by now but it's been a busy fall. In the next month or two things will slow back down. Ill get my motor torn down and start building a motor.

 

[Scott Danforth]

What cam should i use? Will not be upgrading to behive springs or machining for more lift.

Target goal is 300 hp.

I just need that flat tappet cam recommendation

Keep in mind, your '78 motor is crankshaft rated, everything after '85 is prop rated

to get to 300hp prop hp on your motor would be easier if you would run behive springs or spend the $50 and machine the guides as most cams require it.

the cam I would recommend for a flat tappet in a boat is the XM262H, however you will need to address the valve lift with any of the aftermarket cams

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=99&sb=2

 

[Scott Danforth]

I will make a call to crane. Its too bad the new ls engines take so much money to run in our boats. I keep running into the 5.3 ls engines for next to nothing.

Programming, exhaust, closed cooling system. Would cost 5k to run a 500 buck engine.

I should have already had my motor pulled by now but it's been a busy fall. In the next month or two things will slow back down. Ill get my motor torn down and start building a motor.

you can get a dizzy drive for the front of an LS motor, get a carb and drop it in if you want to swap to LS https://www.summitracing.com/parts/...PZ9RRpf2lqbt0kCLg6wWJApnQdqJXLYBoCGDQQAvD_BwE

 

[scoflaw]

Why would you want to do that ? Best features on that LS are no diz and fuel injection which will come with his take out. Run the ECM that came with the motor, have it reflashed to delete the vats. Bigger issue would be exhaust and O2 sensors

 

[Scott Danforth]

Why would you want to do that ? Best features on that LS are no diz and fuel injection which will come with his take out. Run the ECM that came with the motor, have it reflashed to delete the vats. Bigger issue would be exhaust and O2 sensors

because the factory ECU is not J1171 compliant

 

[scoflaw]

Not that anyone is looking under the hood. How bout them exhaust manifolds...do they even exist ?

 

[Scott Danforth]

LS motors have been used in marine applications since 2009, so manifolds both with and without a CAT are available

the issue with using non-J1171 compliant stuff is the boat blows up

 

[dohcdelsol93]

If i did ls i would first have to get a closed cooling system. About 1500

Next ls manifolds...another 1500ish if not more

Then there is the tuning. It will have to be closed loop. The best way to get the most mpg out if it after adding the marine manifolds and marine cam is a custom tune. A socketed ecu, custom harness or mega squirt plus paying a tuner to come on board and fine tune everything so it's perfect...maybe 2500

A lot of money for a 500 buck engine.

I can built a dozen 350s for that price...or 2 or three and spend the rest on fuel

 

[dohcdelsol93]

While i do agree that keeping all electronics on the boat marine grade is and and should be top priority, if you build a proper fuel injected engine is it not much safer anyway? Sealed high pressure fi system. Your fuel tank shouldn't be venting below deck. Your pcv valve should be venting into a sealed intake. And a proper built cool air intake would be sealed in the engine bay and route to suck cool clean air from outside the boat and not hot air from inside the bilge area.

Im not saying that it would be a good idea to run a car starter or alternator. But the carb its self, an open vent prone to flooding is what makes sparks so dangerous. You'll occasionally spring a leak at the fuel pump but getting a carb that has zero gas fumes is impossible.