Help with planning out an engine

[wretched73]

I'm planning on taking my 350 block and boring it .060 over and i want to get somewhere in the 500-550hp range and run on pump gas. I have a good bit of money saved up for it and I want to start collecting parts to put it all together. Can someone help me decide on where i should start looking to get more information on what I'm going to have to do? Or tell me what I'm going to have to look at to reach my power gains? IE head flows, compression, domed vs flat top pistons etc...

I'm going to have help from my buddy and his dad who have built several motors for their race cars (dirt track) but I'm just trying to find a broader range of information.

Anything will help, thanks

[LTb1ow]

Planning on spraying or boosting in the future?

Budget?

I don't know how good quality a gen 1 crank is, but you may want to spend the extra money and stroke it.

[WildBillyT]

Planning on spraying or boosting in the future?

Budget?

I don't know how good quality a gen 1 crank is, but you may want to spend the extra money and stroke it.

If he's going for 500-550hp he should probably go with an aftermarket crank (maybe a GM forging but I wouldn't trust a GM casting to that level at minimum), and if you are doing that you might as well stroke it.

Wretched, how much $ do you have for this?

[sweetbmxrider]

yeah, what exactly is your budget? it adds up quick. half will probably be bottom end and half will easily be the top end. is 60 over safe on a gen 1? i know its very close on a gen II.

what are your goals besides 500 550hp? what do you plan on doing, drag racing? have you budgeted for the trans, ds, rear, and suspension? supporting mods for motor?

[GP99GT]

destroke it...327 and rev to the mooooooon

[Pampered-Z]

Agreed with going 383, much easier to make power with the extra cubes, plus better then going 60 over so you leave room for a rebuild in the future.

From a high level suggestion ( and assuming you looking at running pump gas ).

I would suggest that first you select your heads, the chamber size is going to dictate when piston you select ( pump gas = 9.5 static CR. )
The head flow will influence your cam selection. Making that level of HP N/A is going to require you to spin the engine pretty high, so I would look for heads that have high flow numbers. Maybe look at a set of Brodix or something that can be heavily ported.

[wretched73]

Hopefully like $3 or 4$k is what I'm looking to dump into it. This isn't something that I'm gonna do overnight so i plan on buying a new trans, rear, and driveshaft before the motor goes in. I just want to start looking into how much money I'm gonna need in reality and what I should start looking at

[WildBillyT]

Hopefully like $3 or 4$k is what I'm looking to dump into it. This isn't something that I'm gonna do overnight so i plan on buying a new trans, rear, and driveshaft before the motor goes in. I just want to start looking into how much money I'm gonna need in reality and what I should start looking at

You are going to rip through that money overnight. Good heads OR a good rotating assembly are half your budget already.

I'd recommend building a Vortec based 355. Good bang for your buck. Hell, I'm doing it myself.

[S.J.SLEEPER]

start with a head & cam package by m2 racing (they use a brodix head w/ there cnc program available in 18 & 23 degree)
there package w/ a eldebrock victor jr. intake and a decent carb (demon or hp) will give you 500+hp on a fresh 350
stroking it to a 383 good for a bunch more torque and some hp also

[Stevoone]

I have about $4,000 into my engine (not including mistakes). I put the numbers into desktop dyno and it should have around 500hp. It's a 383 with an Eagle rotating assembley, KB pistons, ~.580 lift solid roller cam, Holley heads and a Victor Jr intake. Can't wait to fire it up

[S.J.SLEEPER]

hey, where you get that desktop dyno program? always wanted to check that out

[Stevoone]

Found it on a torrent, was also packaged with drag 2003. I put specs in for my friends car and everything was identical to the number his car was pushing, HP,TQ and track times

[wretched73]

Thanks for the advice guys

[SteveR]

hey, where you get that desktop dyno program? always wanted to check that out

You can get it from Jeg's/Summit. $49 for the basic version or $99 for the advanced.

[WildBillyT]

You can get a 30 day demo of EA pro for free on their site. Blows Desktop Dyno out of the water IMO

[Tokyo Torquer]

Haven't been on this board for a while.. a bit late, but will offer advice anyway You will not be able to make 500-550 hp on a streetable pump gas engine so easy with just a 360ci NA gen I SBC, and that power level would really require a bit of money unless you add some boost. It would be a lot easier with a 400+ci SBC (for 500hp) or 454+ci BBC (for 550hp). 450-480hp is a more reasonable target for 360ci, and even then it would be a fairly healthy street/ pump gas motor.

I dont know your budget, but assuming a tight budget, I would go for a 3.75" stroke Scat crank and make it a 388, 10:1 static compression, Dart 200 or TFS 195 or new big port Vortec heads from GM Performance, about a 238/244@.050 FT solid cam, 1.75" headers, Edlebrock victor Jr. intake and a 750cfm Holley. That may get you close to 500hp.

Think 1.2 to 1.3 hp per cubic inch for a healthy NA motor on pump gas.

mike

[r0nin89]

Yeah when I finally get mine together its going to be:

Sportman II heads
268 or 274 comp cam
406 with a SCAT rebuild kit
Victor Junior
750 DP

Should be in the very high 400s on HP and around 525 on torque. The best budget route is to go big cubes and vortecs. Good for 500ftlbs and 425 hp. Check out "The Imitator" Build from one of the major magazines. Just google it.

[WildBillyT]

Yeah when I finally get mine together its going to be:

Sportman II heads
268 or 274 comp cam
406 with a SCAT rebuild kit
Victor Junior
750 DP

Should be in the very high 400s on HP and around 525 on torque. The best budget route is to go big cubes and vortecs. Good for 500ftlbs and 425 hp. Check out "The Imitator" Build from one of the major magazines. Just google it.

Coulple of questions. Why the sportsman IIs, and why a victor Jr with a cam that doesn't match its RPM range? An air gap is a better choice to around 6000-6500.

[r0nin89]

Coulple of questions. Why the sportsman IIs, and why a victor Jr with a cam that doesn't match its RPM range? An air gap is a better choice to around 6000-6500.

Sportsman IIs only because I'm trying to keep it on the cheap but we'll see what happens. Guy at work is trying to talk me into Dart Iron Eagles.

And the Victor Junior is simple based on the fact that quite a few people I've talked to have preferred the victor junior to the air gap and felt a major lower end loss with the air gap.

Nothing is set in stone though. I'm doing plenty of research before I buy a single thing.

[WildBillyT]

Sportsman IIs only because I'm trying to keep it on the cheap but we'll see what happens. Guy at work is trying to talk me into Dart Iron Eagles.

And the Victor Junior is simple based on the fact that quite a few people I've talked to have preferred the victor junior to the air gap and felt a major lower end loss with the air gap.

Nothing is set in stone though. I'm doing plenty of research before I buy a single thing.

Odd since the Vic jr powerband starts at 3500.

[r0nin89]

Odd since the Vic jr powerband starts at 3500.

Got me. Havent looked at anything personally yet for intakes. perhaps I have my manifold backwards.

[wretched73]

Sooo to drag this on a bit longer I have made a few changes in my ideas and have done a little bit more research into this and hopefully Im a little closer in the direction I need to be. Any criticism is welcome.

First off new goal is 400-450hp, just want a good healthy motor to use in weekend cruising and trying my luck at the track every now and then. I'd like to try and keep my budget around $3500. And also .060 over bore, I figure its just a cheap stock block so why not do the extra bore? So far i have picked out:

Possible heads:
http://www.summitracing.com/parts/DRT-11310010P/

Possible pistons:
http://www.summitracing.com/parts/UEM-IC728-060/

I figure with those two items picked I can get an idea of where I need to go for the valvetrain/cam. I'd like to redline at about 6500 rpm which should be safe enough for a stock rotating assembly

[LTb1ow]

Sooo to drag this on a bit longer I have made a few changes in my ideas and have done a little bit more research into this and hopefully Im a little closer in the direction I need to be. Any criticism is welcome.

First off new goal is 400-450hp, just want a good healthy motor to use in weekend cruising and trying my luck at the track every now and then. I'd like to try and keep my budget around $3500. And also .060 over bore, I figure its just a cheap stock block so why not do the extra bore? So far i have picked out:

Possible heads:
http://www.summitracing.com/parts/DRT-11310010P/

Possible pistons:
http://www.summitracing.com/parts/UEM-IC728-060/

I figure with those two items picked I can get an idea of where I need to go for the valvetrain/cam. I'd like to redline at about 6500 rpm which should be safe enough for a stock rotating assembly

Erm, a 60 over and new pistons is a pretty deep dive... why not just do it right and get a new crank with new rods?

Seems silly to me to do all that work and not do that.

[wretched73]

Erm, a 60 over and new pistons is a pretty deep dive... why not just do it right and get a new crank with new rods?

Seems silly to me to do all that work and not do that.

New crank and rods is a hefty amount to add into the budget so my idea was to save money and run the stock ones. My buddy's dad turned me onto that idea because he has run much more intense setups on stock rotating assemblies

[LTb1ow]

I don't know if this is correct, but a .060 over piston on a stock rod is not a good thing I thought. And yea, I am wrong, at least for LT1 world, aftermarket pistons are lighter.

F = Kg x Piston G's x 9.81m/s^2 x .2248

Stock Piston

@ 6500rpm = .532 Kg x 2720 g's x 9.81 m/s^2 x .2248 = 3191 lbs of F
@ 7000rpm = .532 Kg x 3160 g's x 9.81 m/s^2 x .2248 = 3707 lbs of F

Now switching to a Mahle 4.030 stock replacement piston (5.7" Rod)

@ 6500rpm = .464 Kg x 2720 g's x 9.81 m/s^2 x .2248 = 2783 lbs of F
@ 7000rpm = .464 Kg x 3160 g's x 9.81 m/s^2 x .2248 = 3233 lbs of F

Now going to the 6.0" Mahle piston

@ 6500rpm = .429 Kg x 2690 g's x 9.81 m/s^2 x .2248 = 2544 lbs of F
@ 7000rpm = .429 Kg x 3120 g's x 9.81 m/S^2 x .2248 = 2951 lbs of F


Bret Bauer work ^

Just seems like backwards thinking man, you are gonna pay to have the block cleaned up, bored out etc... a new crank and rods is not that much more. And you will need to re balance it all for the new pistons, so again, why not save up some more and do it all right, and at once?

Scat rods for ~200, and a new crank for ~500 area, ARP hardware in there and you have a stout bottom end.

Also, what are the flow numbers on those heads? Any thoughts on what kind of valvetrain you are gonna be running to shift round 6500?

[BigAls87Z28]

Good point. No sense in spending all that money on boring the block without running into problems with the rest of the engine parts.

[wretched73]

You guys keep saying don't waste my money boring the block and keeping a stock bottom end....

What would you recommend for crank/rods?
If I'm spending the money to bore the block and buy a crank and rods, should I just stroke it at the same time?

[sweetbmxrider]

you make your power in the heads, spend money there. have the block cleaned up and if it needs to be bored, have them bore it. to get to 500hp na, you'd be better off with a 383/396 crank imo. head flow should be in the low 300's at max lift. compression ratio should be around 11:1. really just gotta talk to people who do it every day and see what they say works best for you.

power is made in the top end.

[wretched73]

Thanks for the input, but just to let you know I mellowed myself out a little and decided to shoot for something around 400-450 na

[sweetbmxrider]

brandon just hit 455 with his 383 on 11:1 compression and head flow in the 280 range at .600 lift. you could do it with a stock bottom end though, just need ported heads and a decent cam.

[WildBillyT]

brandon just hit 455 with his 383 on 11:1 compression and head flow in the 280 range at .600 lift. you could do it with a stock bottom end though, just need ported heads and a decent cam.

LT1, right?

Wretched, what type of running gear do you have for this? MSD, carb, distributor, etc?

[LTb1ow]

LT1, right?

Brandon's is, but still a regular ole SBC should be simple to get those numbers, flywheel at least.

[WildBillyT]

Brandon's is, but still a regular ole SBC should be simple to get those numbers, flywheel at least.

Absolutely. I was just thinking of the 11:1 on the street with an all cast iron Gen I.

I stand by my previous statement. Vortec 355.

[LTb1ow]

I am not sure of the practicality anymore, but if you can get a 400 crank, and clearance your 350 block to fit it in, then get some 5.7 rods, KB hypercraptic pistons, and a final CR of around ~9.8:1 ... throw some 186 heads on there with a good port job ~240cfm@60 and a CC 270H on a 106....

voila... ~420hp

David Vizard is the man.

And again, join a forum more focused on SBC shiznit...

[WildBillyT]

I am not sure of the practicality anymore, but if you can get a 400 crank, and clearance your 350 block to fit it in, then get some 5.7 rods, KB hypercraptic pistons, and a final CR of around ~9.8:1 ... throw some 186 heads on there with a good port job ~240cfm@60 and a CC 270H on a 106....

voila... ~420hp

David Vizard is the man.

And again, join a forum more focused on SBC shiznit...

I'd skip those heads and cam for more modern ones.

[Syzygy]

i have a touch over 500hp on my 360 on pump gas. and i even have procomp heads. ported to hell, and back, but they only cost me $700 :lol: