Maybe the answer isn't LS1

Strike_Zero wrote: ...The LT1 is not a scary motor. The opti-spark issue a well documented and overly misunderstood. Get the vented one and keep the water pump from leaking on it. Simple fix . . .

Yes I learned that first-hand, having owned a 1995 Z28. That thing cost me a bloody fortune. If the engine was in something where it was easy to get to, maybe but if not, never again. Caused me to swear off GM entirely...

Toyman01 wrote: I have two Chevy 350 blocks. One is a car engine and the other is a very low hour Mercruiser marine engine. The car engine will need a complete build, the marine engine will need the heads gone through due to a boat fire. If my memory serves me correctly the marine engines have forged internals.

Since about 1976, marine engines are carbon copies of vehicle engines. It used to be that they had forged parts, 4 bolt mains, and wider tolerances to use 50wt oil. Not anymore. I have three Mercruiser engines and one Volvo Penta engine - all of them carry the same casting numbers, part numbers, and many other things in common with the street engine. All three of them are 2-bolt mains with cast cranks. I do have one 1985 inboard Ford 351 that has 4-bolt mains, but that is mostly due to the fact that many 351s had 4-bolts from the factory, even in cars.

The good news is that you don't even need to think about exotic parts in an SBC until about 6500 rpm or 600 hp.

With 217 heads, make sure its not a 305. The 305 is 87% the displacement of the 350, but its far from being 87% the performance potential. The old saying "its what I have and i can't afford another engine" doesn't fly with the 305/350 debate. You can typically build 400hp on a 350 for less money than you can make 350 hp in a 305... including the cost of purchasing a 350 core.

kb58 wrote:

Strike_Zero wrote: ...The LT1 is not a scary motor. The opti-spark issue a well documented and overly misunderstood. Get the vented one and keep the water pump from leaking on it. Simple fix . . .

If the engine was in something where it was easy to get to, *maybe* but if not, never again

HEHE . . . I can agree with that. That motor was BEAR to work on in a Camaro.

It was pretty easy to work on in an FC.

So, using the marine short block, build me on paper a moderate HP high torque SBC. Something in the 300+hp 400+tq range sounds like a lot of fun in a first gen RX-7. The compression ratio on the marine engine is 9.4 to 1. The heads on it now are 64cc "217" heads.

The 217 heads should support 275-300 hp, but they're nothing to write home about. Vortec heads would keep the same basic port volume but add about 30-35% flow.

With the 217s, use a cam in the 214 intake/224 exhaust range on a 112 LSA. That will get you squarely around 300hp/400tq. With Vortecs, just use a super mild cam that is one step up from stock - maybe 204/214 on a 112 LSA. 9.4:1 is fine to use on pump gas with the 217s, but you'll have to keep things in the higher octane range. With Vortecs, you can do the same with 86 octane.

I do not know what you want to spend, but this seems to be reasonable and much more of a bolt in unit

http://www.partsgroup.com/store.aspx?category=RX8-Engine&Page=0

pilotbraden wrote: I do not know what you want to spend, but this seems to be reasonable and much more of a bolt in unit http://www.partsgroup.com/store.aspx?category=RX8-Engine&Page=0

A carbed V8 would be a MUCH simpler install.

I'm surprised no one has mentioned turning one of those 350s you've got into a 383 stroker...

I have the parts to sell him for a 383, but after what I paid for them... not cheap.

4340 Forged stroker crank, forged H-beam rods, billet steel main caps Overkill

Raze wrote: I'm surprised no one has mentioned turning one of those 350s you've got into a 383 stroker...

Very true, but unless he's going north of 400 hp or putting it in a heavy car, I personally don't think he needs the cubes to support his goals.

I keep coming back to a basic 350. Simple and with reasonable power. I guess I need to pull the two engines I have down and see exactly what they are. Probably won't happen this weekend though. The Abomination had to be pushed on the trailer this weekend. It's fuel pump time.

Yeah, and you are adding around 200 pounds right smack over the front axle, with part of it actually sticking out past it. HP numbers ain't everything, bub.

I'm too tired to hotlink, but you guys can't possibly have forgotten Grannys recent posts of the V8 Fb with his recipe for ferocious setback.

Curmudgeon wrote: Yeah, and you are adding around 200 pounds right smack over the front axle, with part of it actually sticking out past it. HP numbers ain't everything, bub.

Yeah, but my Roadmaster would outrun it in a straight line.

It isn't going to be a autocross car much anymore. The Abomination is much better suited for that. I'm probably going to put to A/C back on as well. I want to set it up for weekend cruising.

The idea of a tarted up Chevy V8 that will spin up to 7800 rpm reliably does sound appealing!

If you did not already have the SBC's LM4 would be my next suggestion. Cheep lightweight 300-325 HP out of the box and for short $$$ you can have 400 hp. I picked one up complete with all accessories (inc AC comp) computer wiring harness about a year back for $600. Yes it had 80K on it but I got to here / drive it before it was pulled from the vehicle and it came with pretty good service records.

You may want to consider the total cost of rebuilding the SBC versus the cost of a 60-80K running LM4 or even a LM7 (cheaper even still due to being cast block)

I have seen a few recipes for these high revving 4.8L engines but has one here actually built one? Or have a link to a build?

A screaming v8 sure does intrigue me even though I don't know what I would bolt it into. I have an LS1 in my camaro and it has plenty of life left in it at 90k but I'm always looking for a fun project.

For the FB I would use the 350 engines that are already at hand. The LS-anything would be nice, but I think the 350 will be plenty powerful to scare the crap out of you in such a light car.

In reply to Strike_Zero:

Does it matter if its an old 4.8L (classic 99-07) or late 4.8L (07+)? My friend and I are hunting for motors at the moment and would like to get started on this

Classic or late . . .

I'm going use a classic for my build since I have a camaro harness and don't have to futz about the reluctor wheel issue on late motor.

I'm pretty sure the 243/799 heads started to show up on the 05 and up truck motors.

There aren't any builds that I know. . . most guys boost it or trade them for ported throttle bodies (I hate it that missed that one).

Ls1truck.com and performancetrucks.net have some guys running some mild to outrageous combos for the 4.8L. Everything from 300whp builds to 7700rpm turbo'd monsters . . .

How about keeping the marine shortblock and getting a set of ~$600 aluminum heads from Skip White (skipwhite1 I think) on eBay? Find a cheap, flat-tappet Summit cam kit and maybe a Summit carb/aluminum intake combo to finish things out.

The heads are 64cc so your CR shouldn't change but you get better flow and less weight. That should put you at about 330HP/380ftlbs. At least, that is what desktop dyno tells me while I'm dreaming up combos for my El Camino.

Another option would be a GenIII/IV with an Edlebrock carb intake. CarCraft did that with a stock 5.3 w/ headers and dyno'd 350-ish HP, IIRC. There is no way to hide that under a stock hood though. And the intake (w/ MSD box but no carb) costs about $1000.

In reply to rmarkc:

You been reading my mind or something...

I found the Skip White heads on ebay last night. They are high on the list of possibilities. I need to get the engine on the stand and open it up. That's probably the direction I am going. A decent bottom end with a good set of heads and intake should put me in the HP range I would like. It'll probably get a Quadrajunk for now with plans to TBI it later.

If you were going to buy a manifold or heads or distributor or anything for an older SBC or LT1 anyway you might as well go with the 4.8L/5.3L/6L truck motor and add a carb intake and MSD ignition controller for $600. Comparing bone-stock internals you get better flow and less weight due to the aluminum heads. The standalone MSD box also supports boost and is fully programmable, making you a carb box, intercooler, and pair of turbos away from rampant boosted LSx goodness.

Don't buy the Edelbrock kit, it costs $100 more, has too much advance, and the ignition box isn't programmable. In this case ala-cart is best.