Trying to pick an engine!!

[Phantom]

This thread is ridiculous.

[Guest Bob L]

I thought of the Northstar before, but it really is not what I am looking for. I specifically am looking for opinions of the engine builds mentioned in the first post.

 

OK, here it is. Building a Chevy 302 for your application is, IMO, stupid. I once suffered under the same delusions you did about high RPMs; unfortunately, I spent the money on building up one of these motors. It was consistently clobbered by larger CI engines and I spent lots of time and money on the valvetrain.

 

The second delusion you seem to suffer from is that the short stroke and high rod ratio of the 302 will allow it to more reliably rev to high RPMs. 350s don't have a lot of lower end problems. You also completely IGNORE the most common cause of engine failure - valvetrain problems. A short stroke does NOTHING for valvetrain reliability. In fact, it hurts, because when you are losing your stoplight grand prix due to lack of cubic inches, there is a natural tendency to spin the engine faster.

 

So my opinion of the whole 302 thing - misguided.

[Guest Nic-Rebel450CA]

This thread is ridiculous.

Um, if it is rediculous, dont read it and dont respond to it. Pretty simple. Your personal opinion provides nothing for the thread. Thanks for any attempt that may have been at a helpful statement though.

 

...

So my opinion of the whole 302 thing - misguided.

Woah there junior member. The purpose of HybridZ isnt to flame people for having ideas different than yours. No one said I intend to race larger cube engines, or if I even care if I would lose. Not everyone is here to build a car to try to beat everything on the street. Some of us have the ability to accept the fact that we cant build a car that can beat everything on the street, and also have no need for one.

 

BTW, check your facts. It is a known fact that a shorter stroke bottom end has the capability of holding up under higher rpms better than a long stroke. Nowhere did I indicate that I was ignoring valvetrain problems. Perhaps you assumed that I would be using stock valvetrain setup because I did not mention otherwise. I did not mention valvetrain because all small block Chevys basically can have heads built equally.

 

I appreciate that you have tried to build a similar project in the past, but there is no delusion or misguidedness to the idea of a 302, or 283. They can be built to rev high. Sure, I wont beat everything on the street, but hey, neither will you. Doesnt matter to me, do it matter to you?

[Guest Nic-Rebel450CA]

For those of you who ARE trying to help, I appreciate the help...

 

I think I have narrowed it down to:

302 (Built by putting a 283 crank into a Gen 1 350 block with bearing spacers)

302 (Possibly able to be built by putting an L99 (4.3L V8 ) crank into an LT1)

And I have decided to shoot for 270-300HP at the crank.

 

The 283 and the 4.3L L99 have basically been ruled out because of the bore. I just dont see it likely that I will be able to build heads to flow well enough. The HP was stepped down because I realized that I can be more conservative since this is a light car.

 

Now the question basically comes down to what my options are for heads for the 302 build up. (Oh ya, and someone earlier mentioned FI, I do plan to go with FI). Can the LT1 and Gen 1 SBCs use the same heads, or does either have a better selection? I am under the impression that Gen 1 engines have more performance parts and better priced parts, but that has all been hearsay so I dont really know.

[dmyntti]

The Gen1 and LT1 use different heads. The LT1 is reverse coolant flow. I think that they can be adapted but doubt it would be worthwhile. The LT1 heads will flow enough air for your goals as will any decent aftermarket Gen1 head and some stock ones. I personally like the 302 LT1 option for its feul injection setup but if you are going to spin it up high you will need an aftermarket computer as I think the LT1 computer won't go above 7000 rpm. I could be wrong though.

[Guest Bob L]

Woah there junior member. The purpose of HybridZ isnt to flame people for having ideas different than yours.

Are you suggesting a correlation between post counts and knowledge' date=' education, experience, or common sense? No offense intended; I was trying to save you from making the same mistake I did in building a 302.

BTW, check your facts. It is a known fact that a shorter stroke bottom end has the capability of holding up under higher rpms better than a long stroke.

While I agree that a shorter stroke induces lower forces on the lower end than a longer stroke at the same RPM if the increased compression height does not increase the reciprocating mass appreciably, a 350, 383, or 400 can make the same HP more reliably than a 302 or a 283. The more popular (larger) engines enjoy the economies of scale for a reason.

 

Perhaps you assumed that I would be using stock valvetrain setup because I did not mention otherwise. I did not mention valvetrain because all small block Chevys basically can have heads built equally.

I assumed nothing. The inertial forces go as the square of engine speed. To get the same HP with a smaller engine means the valvetrain forces go up disproportionately. If you view the valvetrain investment as a sunk cost, why give up the free horsepower associated with more stroke? If you build a 350 lower end with good parts, esp. rod bolts, the valvetrain is going to be the headache, not the lower end.

 

I appreciate that you have tried to build a similar project in the past, but there is no delusion or misguidedness to the idea of a 302, or 283.

I didn't try to build it, I built it and ran it on the street for a couple of years. I believe a 302 or 283 is misguided, but let's agree to respectfully disagree.

[Heavy Z]

Your points are very well articulated, Bob. One thing to keep in mind is that you purpose-built your 302 to kick a$$ on the street, only to be disappointed by the outcome. Nic isn't trying to build the fastest car possible but is intrigued with an oversquare engine. He may drive it and be completely happy, or get used to the power, want more, and move up into some bigger cubes. A good point you made is that if he goes this route and builds a motor that can rev to the moon, well, the low end will take it but the valvetrain might not.

[Guest Nic-Rebel450CA]

Woah there junior member. The purpose of HybridZ isnt to flame people for having ideas different than yours.

Are you suggesting a correlation between post counts and knowledge' date=' education, experience, or common sense? [/quote']

 

No, as the part you quoted stated, I was merely informing you as a newer member to the forum that the purpose of this forum isnt to flame others.

I appreciate your knowledgeable input, just not the form it was presented in.

Thank you.

[jonzer12]

I love high reving engines, my current car has a 2.5 liter v6 that reds at 8k and is a complete dog below 4k, that said there are a few things to consider here besides engine mechanics

 

I totally repect your statements about not having to beat other cars and wanting a 302 or similar engine because its characteristics appeal to you, they appeal to me as well. I am not a fan of big blocks, muscle cars or anything other large cars. The idea of 400 hp in a 4000 pound car is rediculous when a 200hp engine in a 2000 pound gives the same performance with typically better handling and braking and better mileage.

 

There are other aspects not being considered in this discussion tho. If this is purely a street machine you do not want a high reving engine. There are reasons for this, none of which will make sense till you have been through it.

 

-a small block screaming at 7k will piss of neighbours, people sleeping, and attract police like its nobodies business.

 

-being that you can build a higher displacement engine for the same weight and typically cheaper logistically it's a poor value per dollar and per pound to go with a smaller displacement

 

-street driven to me = light to light = low end power, you doing to need lots of cam for that high reving engine which will kill your lower end.

 

-big cam = poor idle = poor street engine

 

-low end grunt relieves downshifting around town.

 

That said I love the fact that my engine is happy cruising along the highway at 4-5k and the sound downshifting at 7k on narrow streets never gets old. Unfortunately after being pulled over more times than I can remember, being afriad to rev it up late at night for fear of attracting attention and the lack of power below 3000 rpm gets old quick in a street machine. For those wondernig I have a stock muffler but with other modifications my car is very loud at high revs.

 

I don't think people are trying to knock your idea its just that most will problably agree that once is all said and done you will probably be happier with a larger displacement engine. An as close to stock engine that will meet your performance goals is always a good idea in a street car IMHO.

 

Wow, I typed alot!

[Guest Nic-Rebel450CA]

Good points Jonzer, and I have thought of those things. However, the common statement about high rpm engines bothering the neighbors is really irrelevant unless one feels the need to be redlining it in first gear in the middle of the night. As far as any lack of power at the lower RPM, a properly built 302 with about 300HP peak will still have more bottom-end then my 280 engine has at it's top end.

 

I understand that there are many people that do not feel that one of these engines would work for them, and may try to provide information to confirm, however, I am not asking if I should pick one of these engines or something else, I am asking which one of these I should pick.

 

I guess I need to be more specific with my question..

Since I have narrowed it down to making a Gen 1 302 or an LT 302, my question is simply which of those two is going to have the best selection of performance parts available that will work for my build.

[80LS1T]

I think, if its possible, the LT1 302 would be the easiest way to make a reliable 300HP engine. Its very easy to make 300HP with the LT1 even if its destroked. The FI will also help with the driveablilty issues that some of the other guys are talking about.

 

I say research the LT1 302 possiblilties and go that route if possible!

 

 

Guy

 

P.S. I think that some of you guys are being a little harsh on Nic. He has clearly stated that he doesnt care if his car is that fastest or if it is the most cost effetive HP to $$$ ratio. I think we all know that more cubes = more power. Even if what some of you guys are saying is true and that this engine wont last....let him find out for himself. We are all big boys and girls here and I think we can all make our own decisions.

[Guest Les Derfler]

A couple of things to think about. Thick bearings... probably not great idea for an engine that you want to run at high rpm's and high h.p. figures. I looked into that a few years back and at that time it wasn't all that dependable. Haven't looked into it lately though. It wouldn't hurt to talk to some "good" machinist's no matter which way that you go. They can really help you out a lot.

 

Are you real sure that your h.p figures are realistic with those cubic inches? It does take 350 flywheel h.p to do what you stated as a goal. What did a stock 283 put out for power? Even the vette engine wasn't even close. Even when you talk 302 they are hard to find (read almost impossable) and the ones that you are looking at building do not have all the good stuff that made the 302 a street killer. Even the good 302 didn't put out 350 h.p. as I recall. Maybe somewhat close? I don't remember but the factory specs were somewhat skewed anyway. I doubt they put out 280-300 hp. as installed with exhaust, but someone might correct me there

 

I am not saying that it is impossable but you will need some "really" good heads for this to work. After all if an engine put out such and such h.p. back then you will have to re-engineer the basics in order for it to produce nearly double than it did from the factory.

 

I would suggest aftermarket. There are many good ones out there that would do the trick. Would that fit your budget? I am not trying to be negative, but after playing with this type of stuff for many years ( I am now a grampa and still at it) I am just saying that this engine will need to be "very" well planned or you might end up dissapointed and wasting $$$ that you could have spent differently and been more successful. I also realize that this was on your mind when you started this thread, so I hope that some of this is somewhat helpful.

 

Les Derfler

510 Funatic

280ZX 350/TT project

[Z-Dreamer]

If it was ME, and it's not, I would build a 350 sbc using a aluminum 400ci block, like the sprint car boy's run, I have one! Then use a 3.00" forged steel crank and 6.25" H-beam rods and custom pistons to make a ultra-lite weight 11:1 comp 350 that will run on 87 octane and make well over 500HP with the right cam and heads!

 

But that's just me:)

 

Mark

[Guest Les Derfler]

Hey ZDreamer where did you ever get a block like that? Do you think that it would fit in Sant'as sleigh I would sure be nice for my TTsbc 280ZX

 

Les Derfler

[Guest HBskinheadZ]

I also would suggest building an all aluminum SBC with 8.5/1 compression and headers, it is light, reliable, and easy to get 275hp. The block will not be cheap but the rest of the parts will be. "MY .02"

[wheelman]

NIC,

 

To answer your specific question about a LT 302 or the old style. I would lean more toward the LT. It will have the reverse flow cooling which allows a higher CR on pump gas and also the modern FI that breaths well and can be tuned with a computer. Parts for the GEN II chevy engine are becoming more available and you might not be required to use some special spacer bearings to install the crank. I'm not versed enough with the compatibility of the L99 crank into a LT1 block but based on prior posts it would fit without a problem. I would be a little concerned about it's strength but you could probably get a Scat unit that would be much stronger, your talking $$$ though.

 

I don't know how you feel about EFI and the wiring that goes with it but not having to screw with a carburator makes it more than worth the extra effort to me. I believe the LT1 intake breaths well up to about 6500-7000 RPM in it's stock form so with a little port work on the heads and the intake you shouldn't run into problems breathing all through the RPM range.

 

The aluminum LT1 heads can be had for around $250.00 if you look around, granted thats used but good ones aren't hard to find. Thats a whole lot cheaper than after market and allows some extra money for custom port work which will definitely be required to get the HP numbers your looking for.

 

One last suggestion, find an LT1 from a 95 Camaro/Firebird, or Caprice/Impalla SS as the starter engine and be sure to get all the electronics. They are ODBI and can be programmed without removing the EPROM chip. They also have the upgraded OptiSpark module with the vapor purge line.

 

Ken W.

[Z-Dreamer]

Les Derfler, Sprint car racing is popular in Northern California and through a associate of mine I was able to purchase a aluminum 410ci Rodek/Brodix "Outlaw" sprint car long block assembly for pennies on the dollar. This all goes to show that if you search patiently in the right places, you can find killer deals.

 

p.s. Now I just need the money to finish it.

 

Mark