so i have scrapped my original plan on using a 6.1 hemi engine due to size and crazy cost vs a small block build. i have access to the la 360 but am wondering which one is a better platform to build a 7000 rpm turbo engine with. the la engine is next to free which is a great thing but if the magnum engine handles rpm and power better i would much rather spend a little on purchasing a 5.9... opinions please thanks.
la vs magnum
- Thread starter jw97neon
- Start date
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Brian Hafliger
Well-Known Member
The LA should sonic check better in the bores...but I would check them! You want the thickest bores you can get...and the early blocks have thicker main saddles which help keep things where they need to be.
If you'll exceed 650HP, I would recommend an R3 if Indy has any left.
Brian
r3 block wow... i kinda fall right back into cost again lol. i guess horsepower costs either way i look at it. what type of power is a good stock block able to handle? do all r3 blocks use a dry sump oil system? sorry for all the questions. my main reason is to build a driver but a weekend warrior as well. i am hoping to break 700 as putting boost to a engine only makes it easier.
Brian Hafliger
Well-Known Member
It all depends on how much power you get and at what rpm, if the engine ever sees any detonation, how much the engine sees WOT, and what the block integrity is like.
Unfortunately, there is no way to know how long something like this will last! If you build it this way, you have to take responsibility for the failure when it happens and move on. I have a lot of customers that do this, and when they hurt it they fix it and keep going.
As long as you know what can happen and are OK with it, then build away!
Turbo's are easier on engines compared to blow-thru's and NOS due to spool time and nothing mechanical connecting the two.
Brian
fratzog lover
Well-Known Member
A rocker shaft is nice too. I would vote LA.
younggun2.0
Well-Known Member
why does everyone want a 600+ hp street car? ever driven an a-body with a legit 400+ hp. its a freakin handful. you WILL NEVER EVER EVER get any chance to use the full potential of a 700 hp engine on the street. Not to mention the headaches that come with having a street car of that caliber. if your purely building to that number to say you have that much hp under the hood then go for it. If your building a car on a "budget" then 700 hp goals are unrealistic. Id say build what you can afford and forget the numbers. 400+ hp is easy to make and cheaply as well as dependably. Its your money bro but 700hp and budget dont belong in the same sentence. good luck
thank you for the advise. i am aware of the cost and how much of a drive it could be and will be on the road. my neon made just under 350. not much but believe me it was fun drive. my magnum spun the dyno at 403. yes it heavy but can get out of hand. my dream has always been to build a street/track car. using a modern hemi and boost it is very easy to break 600 on a stock engine. you will have to build a small block to get anywhere near that. i was liking the idea due too the fact small block engines are a dime a dozen where a modern 6.1 hemi is looking closer to 4000. i am putting fuel injection on either engine. so that does not count as a cost factor. what becomes a factor is the k frame and front suspension. i like the idea of a small block with a stronger k frame and steering box. hence the question. i am not looking to break records just only please myself. it is not about the number, only that when it is turbo numbers come very easy.
the l.a has the shaft rockers and if you can find a pre 75 block they have the same thickness in the cylinder wall as a 340 but with less bore so thats a bonus..Magnum has a nodular iron crank vs cast for the l.a...Also have better heads,dual quench pads and a better exhaust port,cheap shevy rockers,win lose situation there. I'd go with the cheapest one because i don,t think it will really matter either way..
mopar or no race car!
mopar or no race car!
12.6 in a neon, glad you are out draggin.
If you want to go fast read this and save cash, drop cheap junkyard horsepower in a light a body.
http://www.magnumswap.com/
If you want to go fast read this and save cash, drop cheap junkyard horsepower in a light a body.
http://www.magnumswap.com/
fishy68
Tyr Fryr's Inc.
If I were wanting to build something that made 700 hp and cost was a concern I'd be looking into building a big block. A 470" b block with a good set of heads and a nice solid roller could get mighty close to 700. If you fell a little short a squirt of NOS would easily finish the job. I have to agree with YoungGun that 700 hp on the street in an A-body is crazy HP. A nice torquey 575-600 hp big block would be crazy fast and much more streetable IMHO
A 1988 to 1991 LA Block would be a good one to look for (this is what I have).
Since they have roller cams and the 308 heads on them.
Magnum blocks are ok as well, I'm just not a big fan of their stud (err pedestal?) mount rockers on their heads.
Here are some good info for magnum to LA parts interchange.
(I'm sure you were probably aware of most of them)
http://www.magnumswap.com/using-la-parts-on-a-magnum
*Edit* Correction: 1985-1991 318 (5.2) and 1989-1992 360 (5.9) were roller cam LA blocks.
Mine is a 1991 360 LA block.
Since they have roller cams and the 308 heads on them.
Magnum blocks are ok as well, I'm just not a big fan of their stud (err pedestal?) mount rockers on their heads.
Here are some good info for magnum to LA parts interchange.
(I'm sure you were probably aware of most of them)
http://www.magnumswap.com/using-la-parts-on-a-magnum
*Edit* Correction: 1985-1991 318 (5.2) and 1989-1992 360 (5.9) were roller cam LA blocks.
Mine is a 1991 360 LA block.
moper
Well-Known Member
You will spend more on the LA/Magnum to build a reliable package at that level than you will on a 6.1L. You have to buy all the same parts for the LA plus a block, heads, manifolding, etc.
I wouldn't trust a stock 360 crank at much over 500hp. So right off the bat you are dropping a lot of coin on an LA or Magnum on the rotating assembly. Add in heads, adjustable rockers and shafts and already pushing 4000. That 6.1 hemi probably flows pretty Damn well stock. Is the rotating assembly strong enough for 650? Is a 5.7 a good enough staring point?
thanks everyone for the replies. all are super helpful. i was trying to avoid spending much money on a k frame but i feel this may be the most important part of my build so i am just going to keep putting the dollars away and order a rms k frame first. from there i will decide on engine choice. as i will probably just stick to my game plan and stuff a g3 hemi in it. as i have been checking with local people and i think i may have just found a take out 6.1 where the owner is hurting and needs some cash.
fratzog lover
Well-Known Member
Dont forget Hemidenny makes a k member setup also.
moper
Well-Known Member
I'm not that familiar with the swap but I know guys that have them that didn't swap K frames. Is this a necessity or is it you want the improved handling, etc? I thought it was oil pan, headers, and mounts that were needed just to get the engine in?
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