LTx Replacement... or Mod an Old School 350 SBC

[Guest Mike]

I'm sorry if this has already been addressed, but I didn't find anything posted specific to this.

 

I just purchased a '74 260Z that's been rebodied as a '62 Ferrari 250 GTO. The existing engine is an all cast iron "old school" 350 SBC with few (if any) significant performance mods. I've spoken to mechanics who worked on this car and they estimate it currently has 300 HP or a bit less.

 

I want as much HP and torque as I can afford. I might be able to spend about $5K on the engine, but that's pushing my limits.

 

For performance, weight, technical ease, and cost issues... would it be better to sell the "old school" 350 and upgrade to an all aluminum LTx or maybe an iron LT1 w/ aluminum heads? Or am I better off just installing a roller cam/lifters/timing chain, plus better-flowing aluminum heads and SS headers w/ X-pipe, and a supercharger to the existing power plant?

 

BTW, there may be some overheating issues here in South Texas. I can address that with a better aluminum radiator, high flow fan, thick SS headers, electric water pump (so flow stays high enough at idle in traffic), and a new cam with an updated firing order (Ford Windsor firing order).

 

I also want to upgrade the induction system to something more visually exotic and better-flowing. I haven't decided whether to go for easy/reliable/affordable triple deuces... or go all out with four dual Webers with shorty stacks. The latter is my preference because it better simulates the original Ferrari appearance. But cost is a real issue along with initial setup complications... I can do it... just don't know if I want to :^)

 

The wheels will be changed to Dayton 17x7 standard spoke (front) and 17x9 reverse spoke (rear) with 10 or 12 inch treads on the rear. This will simulate the original car and provide much better traction.

 

The car isn't here yet but following are the few specs I could get:

 

JTR conversion kit??

10.5:1 hypereutectic pistons

Stock iron crank??

Stock unmodified iron heads (which??)

Performer RPM intake... soon to change (see above)

Edelbrock 650 carb... soon to change (see above)

R200 w/ 2.9:1 ratio... soon to add a Quaife

Trans... soon to be 700R4 w/ slightly lowered 2nd gear

 

THANKS!!

 

http://forums.hybridz.org/attachment.php?attachmentid=617&stc=1&d=1149194303

[Bartman]

The only aluminum LTX that I'm aware of if an LT5, which is unlike any other LT engine.

 

In general it really depends on what you want. If you want fuel injection and other upgrades such as reverse-cooling go with an LT1.

With your budget you could definitely get some good horsepower well north of 400. I'm sure you could get the same amount or more modifiying your current setup as well.

 

If you want a more authentic look to go with your car, then maybe you should keep your existing engine and go with the four dual Webers.

[Guest Mike]

Bartman,

 

Thanks for the reply. There are many things I want to update on this car (approximately $5K worth) besides the engine, so cost is an issue... the cheaper the better. I neglected to mention that I want to add an A/C too. There are many things to consider... cost, performance, reliability, weight, weight dsitribution, exotic (Ferrari-esque) appearance, ease of the upgrade, etc. I just need a shove in the right direction.

 

The more I read on this topic, the more I'm leaning toward an LT1 with updated cam, heads, and exhaust. If I can get 450 BHP before any forced induction, that would be fine. I could later add dual turbos or a supercharger to bring BHP to an easy 600 or so, right? Is this easier/cheaper than modding the old 350 SBC? The only down side is complexity of converting to carburation... the quad dual Webers or triple deuces. Too, doesn't the LT1 require a computer, which also controls the transmission?

 

Other possible options are either 383 stroker or a 400 SB. I'm open to options.

 

What do you guys think?

 

ANYBODY HAVE ENGINES OR PARTS FOR SALE???

[Pop N Wood]

Most people wouldn't really consider an LT1 "new school". I don't think there is any real advantage to an LT1 over a first gen SBC other than it is a cheap way to get a good performing fuel injection. In fact, LT1's were made for so few years that they don't have the aftermarket support of the first gens.

 

Unless you use stolen parts, a 450 HP engine is not going to be cheap no matter what generation engine you use. And, if your smart, you don't just "add a turbocharger" to a 450 HP motor. A 600 HP forced induction motor is a purpose built machine. You will build it differently than you will a NA motor.

 

The first thing you need to ask yourself is why do you need 450 HP? That is a really strong street machine and will cost some $$ to get there with an LT1 or first gen motor. If you were starting from scratch, then in my opinion the cheapeast way to get there will be with an LS1 motor. But I can tell you right now you will need to double your budget to put a 450 HP LS motor in your car.

 

If I were you I would forget the LT1 motor (unless you really want fuel injection) and concentrate on building up the motor you have.

 

BTW, most garden variety SBC's are less than 300 HP. But even with 200 some HP the car should be pretty fast. If you got an honest 350 HP you might rethink the need for 450 HP.

[wheelman]

I agree with POP, stick with your current motor and add aluminum heads if you're looking for weight savings. Getting an LT1 and then converting it to carbs would be a total waste of money as you'd be throwing away most of the improvements the LT1 had, the fuel injection. The reverse cooling and relatively high compression are nice but can be done with your current motor and you'd spend a lot less money.

 

Wheelman

[Brad-ManQ45]

Actually, if you were considering Turboing or supercharging, the reverse-flow cooling system of an LT1 engine makes a lot of sense.

 

You can get a streetable 450 HP out of the early chevy, assuming 350 CI, but to do it, convert to fuel injection - I'd recommend the Holley Stealth Ram intake for something really different.

 

I think you're better off and cheaper building what you have and fuel injecting it.

 

If you really want the look, go ahead and fuel inject it with individual throttle bodies - that way you get the look.

 

You can also put in a stroker crank for a 383 for bigger #'s without forced induction....

[Guest Mike]

Pop N Wood

 

All great advice. Thank you!!

 

YOU SAID: Most people wouldn't really consider an LT1 "new school". I don't think there is any real advantage to an LT1 over a first gen SBC other than it is a cheap way to get a good performing fuel injection. In fact, LT1's were made for so few years that they don't have the aftermarket support of the first gens.

 

MY REPLY: Well... when it comes to "performance" engine work... an LT1 is new school to me :^) I haven't had a "fun" car for more than a quarter century and those were old Pontiac Firebirds with 400's and 455's. I'm not really interested in EFI, so an LT1 is out of the equation.

 

YOU SAID: Unless you use stolen parts, a 450 HP engine is not going to be cheap no matter what generation engine you use. And, if your smart, you don't just "add a turbocharger" to a 450 HP motor. A 600 HP forced induction motor is a purpose built machine. You will build it differently than you will a NA motor.

 

MY REPLY: I had read somewhere that a typical LT1 could be SC'd without further modifications. This is one reason the LT1 was appealing to me. If this is false, it's another reason to rule out the LT1.

 

YOU SAID: The first thing you need to ask yourself is why do you need 450 HP? That is a really strong street machine and will cost some $$ to get there with an LT1 or first gen motor. If you were starting from scratch, then in my opinion the cheapeast way to get there will be with an LS1 motor. But I can tell you right now you will need to double your budget to put a 450 HP LS motor in your car.

 

MY REPLY: Because I want to haul-*** :^) But... I can't afford to spend $10K on the engine alone :^(

 

YOU SAID: If I were you I would forget the LT1 motor (unless you really want fuel injection) and concentrate on building up the motor you have.

 

MY REPLY: That's a real possibility... just find some good used aluminum heads to fit my performance needs. Then add a roller cam/lifters, better SS headers designed for my purposes. Add a SS X-pipe and exhaust. Keep the CR below 9.5:1 with forged pistons and stronger rods so I can SC later, etc. Like you said, I should probably just build this power plant to the specs I want.

 

YOU SAID: BTW, most garden variety SBC's are less than 300 HP. But even with 200 some HP the car should be pretty fast. If you got an honest 350 HP you might rethink the need for 450 HP.

 

MY REPLY: This one may be in that 200 HP category (don't know yet) and I gaurantee this won't make me happy. I've owned 450 HP old Firebirds and I wished for more power. I've melted the rear rubber many times to find it stuck to the rear quarter panels. What better way to spend one's tired budget, eh? I hope this answers th HP issue :^) I want to melt the tires.

 

SUMMING IT UP: You suggest starting with an LS1 and purpose build it for my use... OR... rebuild the gen1 as per above... and this will cost me $10K. I guess my real question should be... What are the best mods I can make for a total cost of $5K or less? I don't want just low-end torque. That's easy. I want a smooth hard-pulling ride all the way to 6500 RPM.

[Guest Mike]

WHEELMAN

 

YOU SAID: I agree with POP, stick with your current motor and add aluminum heads if you're looking for weight savings. Getting an LT1 and then converting it to carbs would be a total waste of money as you'd be throwing away most of the improvements the LT1 had, the fuel injection. The reverse cooling and relatively high compression are nice but can be done with your current motor and you'd spend a lot less money.

 

MY REPLY: Yes, weight savings is important. This car now weighs approximately 2600+ pounds. Aluminum heads, radiator, H2O pump and gear reduction starter will shave 80-100 pounds from the total weight and it's all off the front, which is where I want it gone... for improved F-R weight ratio. I'm adding an A/C so this compounds the wieght concerns. I don't car about the EFI because it looks completely wrong on this car.

 

SUMMING IT UP: It's looking more like I should just rebuild the current SBC. THANKS... keep 'em coming!!!

[Guest Mike]

Brad-ManQ45

 

YOU SAID: Actually, if you were considering Turboing or supercharging, the reverse-flow cooling system of an LT1 engine makes a lot of sense.

 

MY REPLY: Oh yeah... I read something about that... now I'm not sure what to do...

 

YOU SAID: You can get a streetable 450 HP out of the early chevy, assuming 350 CI, but to do it, convert to fuel injection - I'd recommend the Holley Stealth Ram intake for something really different.

 

MY REPLY: This is good advice, thank you. But this system looks wrong on a 1962 Ferrari... even if it is fake :^) My ultimate goal is to go with four dual Webers (small choke) for that "Italian-esque" styling.

 

YOU SAID: I think you're better off and cheaper building what you have and fuel injecting it.

 

MY REPLY: This is probably what I'll do... but no EFI... unless I can find an afforable 60's style system. THANKS!!

 

YOU SAID: If you really want the look, go ahead and fuel inject it with individual throttle bodies - that way you get the look.

 

MY REPLY: NOW you're talking!! Umm... do you know where I can find a turn-key system at an affordable price... maybe a good used one???

 

YOU SAID: You can also put in a stroker crank for a 383 for bigger #'s without forced induction....

 

MY REPLY: This is VERY appealing to me. Everyone... please forgive my ignorance... but I thought building a stroker motor invloved more than just replacing the crank. Don't I need to replace the pistons/rods, push-rods, rockers, etc., and ensure enough clearance between the pistons and valves? If all I must do is replace the crank, that's definitely one changed I'll make!!

 

SUMMATION: For 60's styling... stick with the gen1. For more HP/torque... convert to a 383 stroker.

 

THANKS... keep it coming!!

[Guest Mike]

Okay... I'll most likely STICK W/ THIS GEN1... or another...

 

I'LL SEARCH the forums for tech info regarding STROKER KITS.

 

400 SMALL BLOCK... What about one of these? Is it a direct bolt-on replacement for the 350? What about performance gains... and performance parts availability?

[Guest Mike]

WHEELMAN

 

YOU SAID: I agree with POP, stick with your current motor and add aluminum heads if you're looking for weight savings. Getting an LT1 and then converting it to carbs would be a total waste of money as you'd be throwing away most of the improvements the LT1 had, the fuel injection. The reverse cooling and relatively high compression are nice but can be done with your current motor and you'd spend a lot less money.

 

MY REPLY: Yes, weight savings is important. This car now weighs approximately 2600+ pounds. Aluminum heads, radiator, H2O pump and gear reduction starter will shave 80-100 pounds from the total weight and it's all off the front, which is where I want it gone... for improved F-R weight ratio. I'm adding an A/C so this compounds the weight concerns. I don't care about the EFI because it looks completely wrong on this car.

 

SUMMING IT UP: It's looking more like I should just rebuild the current SBC. THANKS... keep 'em coming!!!

[jt1]

My advice-

 

1)Determine your budget and timespan for that budget, i.e. I can spend 5K on it in the next year.

 

2)Research the mods you would like to do, giving each a price and timeframe.

 

3)Give the mods a priority considering price, time, desirability, and how long the car is gonna be on jackstands. While you're working on it, you're not going to be driving and enjoying it, and this kills a lot of projects.

 

4)Proceed with the mods based on the above considerations.

 

There's no one ideal combo. That's why you see everything here from super boosted four cylinders to V-12's. You've got to research possibilities, decide what's gonna make you happy within your budget, then proceed. Nobody can make those decisions for you. Remember that the nice cars you see here, Pete's, Mark's, Clifton's, plus a lot more.....are the result of many years of work.

 

So that's it. I can talk semi-intelligently about 1st gens if you want to go that route, and will be glad to offer my opinions.

 

John

[Guest Mike]

Is this a bolt-in replacement? Do I need an ECU?

 

http://www.paceparts.com/index.asp?PageAction=VIEWPROD&ProdID=178558

[Guest Mike]

JT1,

 

Thanks... all great points!!

 

YOU SAID: Determine your budget/timespan...

 

MY REPLY: I'm lazy and inpatient. I want it easy and now, now, NOW!!

 

YOU SAID: Research the mods... and timeframe...

 

MY REPLY: I'm lazy and inpatient. I want it easy and now, now, NOW!!

 

YOU SAID: Give the mods a priority... price, time, desirability... how long on jackstands...

 

MY REPLY: I'm lazy and inpatient. I want it easy and now, now, NOW!!

 

YOU SAID: ...you see everything here from super boosted four cylinders to V-12's...

 

MY REPLY: I realize this is off-topic but, since it was mentioned... a V-12 is PERFECT since the original Ferrari 250 GTO had a V12... and I LOVE them. But a really decent used/rebuilt BMW V12 is out of my price range, I'm afraid :^( Also, getting 450+ HP isn't practical, right? Too, there's the reliability/longevity factor. Anyone with V12 experience?

 

YOU SAID: ...nobody can make those decisions for you.

 

MY REPLY: True indeed... just looking for some good guidance from knowledgable folks on this forum... and I'm getting lots of it.

 

SUMMING IT UP: Research more... decide what I want... prioritize... be patient... make wise decisions based on my desires... spend gobs of money. Sounds like I'm searching for a girl-friend :^)

[jt1]

To put a LS in, you'll need completely different motor mounts, and a different transmission. Neither of your current ones will match up. That one doesn't need a ECU, so the wiring is a lot simpler.

 

jt

[Guest Mike]

JT1

 

THANKS!!!

 

YOU SAID: To put a LS in, you'll need completely different motor mounts, and a different transmission. Neither of your current ones will match up. That one doesn't need a ECU, so the wiring is a lot simpler.

 

MY REPLY: Different motor mounts aren't too difficult. I'm replacing the TH400 currently in the car with either a strong TH700R4 (4L60) or a strong 5 or 6 speed manual w/OD. Since this is a daily driver, an automatic is preferrable since I often drive in stop/go traffic. BTW, the headers and exhaust will be upgraded to match my performance goals with a heavy-gauge SS system.

 

SUMMARY: A crate LS is a realatively easy swap. Other future mods nullify most cost concerns for the switch.

 

QUESTION #1: Is the LS crate engine mentioned above worth it... considering costs (both obvious and hidden), time, performance gains, reliability/longevity, and... the "kick-in-the-seat-of-the-pants" FUN factor?

 

QUESTION #2: What price might I expect to pay for a good used or rebuilt LS from an individual? Given the initial cost, am I better off buying used... or go ahead and spend the extra cash for a crate engine similar to the one mentioned above?

 

DOES ANYONE HAVE A NICE LS FOR SALE?

[jt1]

Trans options for a LS are the T56 six speed manual OD, or the auto for the LS, I'm not sure what it is. 700R4 fits 1st gens and LT1's.

 

Anything other than a stock LS install is going to blow the 5K budget all to hell. Even that is going to push it. A 450hp LS would push 10K. Do a search on LS1, LS2, LS6, and you'll get an idea what's required, there are several hours good reading there.

 

Good 1stgen info here, a lot of dyno'd combos to give you an idea of what's required for a 450hp 1stgen, which you can get close to for 5K.

 

http://ryanscarpage.50megs.com/combos1.html

 

jt

[Guest Mike]

Thanks JT1... I'll check it out!!

[Pop N Wood]

Anything other than a stock LS install is going to blow the 5K budget all to hell. Even that is going to push it. A 450hp LS would push 10K. Do a search on LS1' date=' LS2, LS6, and you'll get an idea what's required, there are several hours good reading there.

jt[/quote']

 

I'll Roger That. If you want a low miles LS1/T56 pull out from a 2001-2002 Fbody (which are suppose to have the best heads and block oiling) then that is $5k right there. Add another 2-3 thousand to install it. The salvage yards have finally figured out that there are not many of these engines around and that demand is high. Prices went up a good grand since the end of last year. You can definitely do better if you shop around and maybe buy a complete car at a salvage. But $5K is the ebay/wrecking yard price these days.

 

You can get a set up from an earlier year for maybe $3k

 

I was originally budgeting about $8K for a complete pull out swap. But that has now grown to $10k to $12K because I want the whole 450 HP from day one.

[Guest 73LT1Z]

I see you don't like fuel injection... it was a new concept to me a while back, but I've really grown to prefer it over carbs... speaking of "quads", I recall synching the 4x1 (that's 4 x 1 bbl for the younger guys here ) on my Corvair, and still have this motor in my '66. I'd prefer doing a computer setup on the LT1 anyday.

 

One motor that has not been mentioned is the GM Gen 3 truck motor. It is essentially the same as the LS1, just an iron block. There are three varieities, 4.8, 5.3, and 6.0 liter. The 5.3 out of the truck makes more HP than a 1995 LT1. I bought a 32K junkyard 5.3 locally for $400. A decent set of heads (used) can be had for $800. A performance cam will run you $400 new. Add in an intake, oil pan (trucks are too deep), accessories, etc. and this is another $700. Now you have invested 2300 and you have a motor that will produce well over 400 HP, probably the 450 you mentioned. Chevy High Performance did a buld up on the 6.0 and got almost 600 HP out of it NA.

 

Go to ls1tech.com and their sister site performancetrucks.net and browse the stuff for sale and read some of the posts to get an idea of what you can do with one of these motors.