[seanphelps321]

Hi everyone. I'm new to these forums, I hope I'm not out of place. I will be swapping a bigger engine into my 92 Firebird. I have a chevy 350( 1 piece RMS, non roller, I'm pretty sure 87-up) block, making it a 383 stroker. I have all the stock parts that came off of it, but don't plan on using any of the parts I pulled off. When I take the block to be cleaned and all, I'm going to have them bore it to 4.030" and hone it out. I'm trying to get 400 hp out of this build. I plan on hooking up a T56 6spd and 3.73 posi rear to this engine. I've been talking to some people about parts to buy, but would like to get some second opinions and more help.

Right now, I have a lunati 60103 cam and the lifters that cam with the 60103LK kit and a holley 4150 double pumper 650 cfm mechanical secondary carb. But I'm still figuring the rest of my build.

What I plan on getting:
Heads: Modified vortechs, assembled to handle .600 lift. 64 cc http://sdparts.com/details/scoggin-dickey-parts-center/sd8060ra2
Intake: Edelbrock performer rpm air gap http://www.summitracing.com/parts/EDL-7516/
Pistons: Probe 12344-030 forged dish, compression dist 1.425", +20.40cc http://www.summitracing.com/parts/PBP-12344-030/
Connect rods: SCAT 5.7" i-beam rods http://www.summitracing.com/parts/SCA-25700P/
Crankshaft: SCAT 9000 series, 3.750" stroke http://www.summitracing.com/parts/SCA-935050L/

I also plan on zero decking this, getting a CR of 9.45:1 with head gasket thickness of .040". Just wanted to get as many opinions and/or advice as I could.

EDIT: Cam: http://www.summitracing.com/parts/LUN-60103LK/
Carb: http://www.summitracing.com/parts/HLY-0-4777C/

 

[68NovaSS]

Do a search here for 383 build, there is a kazillion of them and tons of information.

 

[my87Z]

skip the probe piston and just buy this kit:
http://www.summitracing.com/parts/ESP-B13004L03053/

i ran a similar rotating assembly up to 6500rpm and made over 500hp with it and never had any issues.

i would strongly suggest going with a hyd roller instead of the flat tappet cam. if you bought it from summit then i would bet that they would take the cam back and credit you toward the hyd roller cam. besides budget, there is pretty much no reason to go with a flat tappet cam anymore. you spend about $300.00 more for the roller valve train but yet you get considerable more power and longevity.

i personally would also ditch the 650 double pumper, it doesn't sound as if you will be using this more as a race car, so there is no real point in the mechanical secondaries. i would suggest getting a holley 3310 750 vac secondary carb.

 

[vinniekq2]

383

what 87z said I kind of agree.What you have there will easily make 400 hp.I like double pump holleys and like roller cams.

 

[my87Z]

i personally like double pumpers as well, but only if the vehicle is being built to do some racing too, if it is being built for mainly the street then the vac secondary carbs will save gas and are just more street friendly.

 

[seanphelps321]

i personally like double pumpers as well, but only if the vehicle is being built to do some racing too, if it is being built for mainly the street then the vac secondary carbs will save gas and are just more street friendly.

The block I have isn't machined to be a roller block. Also, if I used this carb and was just careful about the throttle it would still be fine for street use right? I ask that because I already had the carb and cam. I got them for a cheap price from a guy that was upgrading. The carb is a little used, cam is new of course.

 

[my87Z]

the block doesn't have to machined for a roller cam, they make retro-fit roller cams for these blocks, typically the only adjustments that are needed to be made are in the cam button/timing cover area.

yes you can absoutley use the 650DP on the street, I like the DP's. I just recomend the vaccum secondary carb because it will be easier to maintain for street use. I use a modified 750 double pumper on my street/strip car.

 

[Silver Surfer]

Those Vortec heads typically are cast with 66-68cc combustion chambers. You are very unlikely to get a set with a true 64cc size. You will need to verify this with modeling clay or a burette. Assuming you go with those 20.40cc pistons, that mean your static CR is going to be 9.1-9.2:1. You could send the heads to a machine shop and they can deck them a little to reduce chamber size, but it is probably easier and just as cheap to get some different pistons from the get go. The 18cc pistons in the kit as suggested by my87Z would get to you to 9.3-9.4:1. Are you trying to run on 87 octane? With a nice tight quench from that zero deck and .040" head gasket, you can get more compression with less timing advance and detonation (thus be able to use lower octane).

I think you should probably bump that CR up a little bit to match the cam, and also more compression = more power: http://www.crankshaftcoalition.com/wiki/Cam_and_compression_ratio_compatibility

In my estimation with your setup on that low 9ish:1 compression you should be knocking on the door at 400HP. I have a desktop dyno and will plug the numbers in later and send you a PM.

A roller cam and roller rockers would help achieve your power goals. But the cost of roller cam, retro-roller lifters, correct length pushrods aint cheap! And do you really want to top off that roller setup with factory stamped steel rockers? Heck no!

 

[Silver Surfer]

Here are the numbers from Desktop Dyno 2003. There was not a supplied file for this cam, nor does it seem that Lunati publishes their valve timings like Comp Cams does. I figure this cam is pretty comparable to the Comp Camps XE268 cam so I started with that and edited the few known values that are published for this cam.

You are looking at
365 HP @ 5,000 RPM
425 ft/lbs @ 4,000 RPM

 

[my87Z]

Here are the numbers from Desktop Dyno 2003. There was not a supplied file for this cam, nor does it seem that Lunati publishes their valve timings like Comp Cams does. I figure this cam is pretty comparable to the Comp Camps XE268 cam so I started with that and edited the few known values that are published for this cam.

You are looking at
365 HP @ 5,000 RPM
425 ft/lbs @ 4,000 RPM

I think this is a little conservitive, but not too far off. I would expect to see about about 380hp/430tq.

I took another look at those heads and since they are already 399.99 a piece i would suggest skipping them and going with these;

http://www.competitionproducts.com/...-SB-Head-Stage-1-Pair/productinfo/RHS12317K1/

you are going to spend basically the same exact amount for a pair a of heads that will out perform the crap out of those vortec heads. right off the bat you would be looking at 20-25hp, due to the improved flow + velocity they produce and the extra .2-.3 of compression would you get out of them (if the vortecs are 66-68cc).

I would also recomend you jump to a slightly larger cam (if you refuse to go with a roller) such as this one;

http://www.summitracing.com/parts/CRN-114561/

do not use 1.6 rockers with these though, i would only use 1.5 rockers.

the cam i suggested with the RHS heads, as well as the kit i suggested would get you into the 425hp/450tq range. you will want to run an aftermarket stall with this cam though, around 2800. the cam says that it's band starts at 3000rpm but that is in a 350, in a 383 the band will start at about 2400rpm.

 

[seanphelps321]

Sorry about not replying. Been a little busy. I just got the block back from the machine shop, they bored it .030 over but there was still a problem in the #2 cylinder so it went to .040. So looks like it'll be a 385. They also ground the deck down because it was in bad shape. He said he took .015" off, which should leave me around 9.010" deck. I didn't tell them to zero deck it because I didn't know what exactly I was putting in yet. After looking into the kit that my87z recommended, I decided to go with the Eagle kit. But I was thinking this one:

Eagle Specialty Products B13054L040 - Eagle Street and Strip Rotating Assemblies - Overview - SummitRacing.com

I think they're the same except balance type. With this, I should have .002" clearance. And also, I expecting around 9.68:1 CR. But that was assuming 64cc with the vortechs. So if they're not 64cc, that kind of sucks. I was looking for like 9.3-9.7 CR. I'll definitely look into those heads, my87z. Thanks.

I would also recomend you jump to a slightly larger cam

Now about the cam, I see that the lift numbers are a little bigger on the Lunati and that the adv and .050 duration is larger on the Crane. But in comparing those 2, what set the Crane one above the Lunati to you? Just curious.

 

[my87Z]

i had to go back and look at both cams to see why i would have recomended the crane cam over the lunati cam. I'm actually a bit suprised that i recomended a crane cam, there is nothing wrong with them they are of a very good quality i just dont look at them very often, i think i picked it solely due to it's profile.

the crane cam has a bit more duration which the 385 will like, the lunati has a tad bit more lift but that isn't enough to be felt. the reason i picked the crane cam is because it's ramp rates are a lot more friendly on a hyd flat tappet valvetrain then the lunati cam's ramp rate. your ramp rate in laymens terms is the difference in duration @ .050 and the advertised duration.
ex. crane cam: 234°-296° which is a difference of 62°, this is basically how fast the valve opens and closes.
lunati cam: 227°-268° which is a defference of 41°, this means that on the lunati cam the valve will be opening and closing (.000"-.489"-.000") in 2/3rds the time of the crane cam. 41° difference is absically what you will see on a solid flat tappet cam and is VERY aggressive. which an aggressive ramp rate means extra stress on the rest of the valvetrain.

now the crane cam acutally has more of a slow ramp rate, 62° is a good bit. if i were to build another hyd flat tappet 383 then i would look for a ramp rate in the 50° range. here are a few that i like a bit better than the crane cam, and i certainly like them better than the lunati cam.

COMP Cams 12-212-2 - COMP Cams Magnum Hydraulic Camshafts - Overview - SummitRacing.com
Lunati 00010 - Lunati Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com

this one would probably be my choice, i am a big fan of howards valvetrain products, i have been using them for quite a while with absolutly no problems and their customer service is second to none.

Howards Cams 112141-10 - Howards Cams Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com

and as i mentioned before, i wouldn't go with the scoggin dicky vortec heads for 800.00 when the 180cc RHS pro action heads are the same price and are proven to flow better and flat out perform better.

the Eagle kit you chose is just fine, i've used the 4.030" kit before and it worked great for me. if you match the howards cam, a nice performer rpm intake, a simple holley 750 vac sec carb, cheap HEI distributor (60K volt), with those RHS heads, and a decent set of headers and exhaust then you will be sitting in the 410-425hp rane but the kicker will be the 440-460tq you will make, all while using pump gas.

 

[joelster]

Hi everyone. I'm new to these forums, I hope I'm not out of place. I will be swapping a bigger engine into my 92 Firebird. I have a chevy 350( 1 piece RMS, non roller, I'm pretty sure 87-up) block, making it a 383 stroker.

If it's an '87+ block it should be a roller block. That would be a big plus.

I have all the stock parts that came off of it, but don't plan on using any of the parts I pulled off. When I take the block to be cleaned and all, I'm going to have them bore it to 4.030" and hone it out. I'm trying to get 400 hp out of this build. I plan on hooking up a T56 6spd and 3.73 posi rear to this engine. I've been talking to some people about parts to buy, but would like to get some second opinions and more help.

They will have to clearance the sides for the stroker crankshaft. Down by the oil pan gasket.

Right now, I have a lunati 60103 cam and the lifters that cam with the 60103LK kit and a holley 4150 double pumper 650 cfm mechanical secondary carb. But I'm still figuring the rest of my build.

What I plan on getting:
Heads: Modified vortechs, assembled to handle .600 lift. 64 cc Scoggin Dickey Parts Center SD8060RA2 - SB Chevrolet Vortec Cylinder Head w/ 0.600 Springs for Roller Cams | SDParts - 1-800-456-0211

Iron heads will be cheap, but Vortec heads flow roughly 220cfm give or take a little, and will be adequate for a 383cube engine. I would put an aluminum head with a minimum of 195cc port that flows minimum of 250cfm. Something like this will do:

Summit Racing SUM-162112 - Summit Racing Street & Strip® Cylinder Heads for Small Chevy - Overview - SummitRacing.com

Intake: Edelbrock performer rpm air gap Edelbrock 7516 - Edelbrock Performer RPM Air-Gap Intake Manifolds - Overview - SummitRacing.com

Excellent intake, can't go wrong with that.

Pistons: Probe 12344-030 forged dish, compression dist 1.425", +20.40cc Probe Pistons 12344-030 - Probe SRS Forged Pistons - Overview - SummitRacing.com
Connect rods: SCAT 5.7" i-beam rods SCAT Engine Components 25700P - Scat Pro Stock I-Beam Connecting Rods - Overview - SummitRacing.com
Crankshaft: SCAT 9000 series, 3.750" stroke SCAT Engine Components 935050L - Scat Series 9000 Cast Pro Comp Stroker Lightweight Crankshafts - Overview - SummitRacing.com

It's better to buy everything as one package to save a few bucks. Try ohiocrank.com to see what packages they offer. Their cranks are made in the USA.

I also plan on zero decking this, getting a CR of 9.45:1 with head gasket thickness of .040". Just wanted to get as many opinions and/or advice as I could.

With an aluminum head you can go much higher on the compression than that and sacrifice virtually nothing. I run 11.77-1 and run pump 93. It will run on 91 octane but I don't push it when I run it on that. Personally I would shoot for 10.5-1 to play it safe and still make power.

EDIT: Cam: Lunati 60103LK - Lunati Voodoo Cam and Lifter Kits - Overview - SummitRacing.com
Carb: Holley 0-4777C - Holley Model 4150 Carburetors - Overview - SummitRacing.com

That cam is very mild for a 383. Your hp goals are very low and I'm sure you'd probably hit them or be close with the parts you pick, but next year you may want more power. Just trying to save you on a teardown for next year!

 

[my87Z]

@ Joelster,

many 87' and up sbc blocks were roller but most trucks still came with a hyd flat tappet cam until 92-93' when they started making the first vortec sbc's. they were the ones with the swirl port heads, not the 906/062 vortecs that we all know today.

then you go into telling him to go after building a motor that will be pushing out 450-470hp which his 92' firebird wont hold up to very well. the 400hp goal he has is pretty much right where he wants to be unless he wants to start spending big $$$$ on setting the car up to handle it.

take a look at my profile name, My87z, and ask me how i know. that Z doesn't stand for and old datsun or nissan, it stands for Z-28. my most recent build has me running very low 11.0-11.15" and trust me when you exclude the motor i still have well over 10,000 into the car (not including the purchase price)

 

[joelster]

@ Joelster,

many 87' and up sbc blocks were roller but most trucks still came with a hyd flat tappet cam until 92-93' when they started making the first vortec sbc's. they were the ones with the swirl port heads, not the 906/062 vortecs that we all know today.

then you go into telling him to go after building a motor that will be pushing out 450-470hp which his 92' firebird wont hold up to very well. the 400hp goal he has is pretty much right where he wants to be unless he wants to start spending big $$$$ on setting the car up to handle it.

350hp will grenade a factory 7.5" rearend. 400hp that he is shooting for will pop it in a second. He will need a new driveshaft as well, then the flimsy factory stamped-steel torque arm will have to go, not to mention the stamped lower control arms.

I just have a feeling he will be a little disappointed with those iron heads, when he understands that for a few hundred more he could make more power, run more compression, shed more weight and keep the motor cooler. While the motor is out and everything is easily accessible, spend the coin on some good parts. I'm not telling him to get some cnc'd $2500 set of heads. Just some bang-for-the-buck aluminum ones.

take a look at my profile name, My87z, and ask me how i know. that Z doesn't stand for and old datsun or nissan, it stands for Z-28. my most recent build has me running very low 11.0-11.15" and trust me when you exclude the motor i still have well over 10,000 into the car (not including the purchase price)

I have owned 6 Z-28's ('79, '80, '87 IROC, '91 G92 350, '94, and '95), so you aren't telling me anything I don't already know. My current Z-28 runs 10.5's on pump gas, in street trim. I know all of the weak links in a 3rd and 4th gen. 400hp will find them too.

 

[my87Z]

his 92' already has the stronger 7.625" rear in it with the 28 spline axles instead of the 7.5" with the 26 spline axles. you are right about the TQ arm and the control arms. before i started drag racing my current set up i had a 355 putting out about 390-400hp, I upgraded to a 7.625 rearend from a 91' and I never had any issues with it.

think about this, how many LT1 and LS1 camaro's are out there with a set of headers and exhaust, reprogramed, with an aftermarket intake and just some other bolt on mods. these cars are making about 400hp and still using the same 7.625" rearend. dont get me wrong these rearends are week and will likely be the weakest link on the car with 400+hp/tq but i've seen plenty handle this kind of power without any problems. its the 7.5" rearend with the 26 spline axles which is so much weaker. after saying all this, i must say that with my old set up on my 385, my 7.625" rear didn't last 3 weeks. but it was also putting out 490tq.

I am someone who believes saving the money and doing it right the first time so i understand what you are telling him. I just dont think that is what he looking for. for many people 400hp in a street car is all they will ever care to have. based on the parts OP picked, i assumed that he was on a budget that is why i suggested the iron RHS 180 heads, and believe it or not they actually flow 258cfm @ .500", these numbers came from an independant shop that has flow tested hundreds of different heads on their SF600. most $1000-1250.00 alm heads are right in that range with them so how much would that extra $200-450.00 extra for the alm heads acutally benifit him. they are lighter, but if he's not racing then the extra 50lbs will never be seen nor felt. now for the heating aspect. the alm heads will be easier to cool, but as long as he has a decent electric fan he wont have any problems with the irons heads, on my previous motor set up i used Dart 200cc platinum iron heads and i never had any issues with keeping the motor under 190°.

Yes, would a set of AFR 195's, Brodix IK200's, or Dart pro-1 200's along with a hyd roller cam be his best option for making more power, absolutley. with these he would likely make 50-75 more hp all day but he would also spend another $1500.00 doing it.

Sometimes you have to make recomendations based on what you believe the OP wants, not what you would want. :thumbup:

 

[seanphelps321]

i had to go back and look at both cams to see why i would have recomended the crane cam over the lunati cam. I'm actually a bit suprised that i recomended a crane cam, there is nothing wrong with them they are of a very good quality i just dont look at them very often, i think i picked it solely due to it's profile.

the crane cam has a bit more duration which the 385 will like, the lunati has a tad bit more lift but that isn't enough to be felt. the reason i picked the crane cam is because it's ramp rates are a lot more friendly on a hyd flat tappet valvetrain then the lunati cam's ramp rate. your ramp rate in laymens terms is the difference in duration @ .050 and the advertised duration.
ex. crane cam: 234°-296° which is a difference of 62°, this is basically how fast the valve opens and closes.
lunati cam: 227°-268° which is a defference of 41°, this means that on the lunati cam the valve will be opening and closing (.000"-.489"-.000") in 2/3rds the time of the crane cam. 41° difference is absically what you will see on a solid flat tappet cam and is VERY aggressive. which an aggressive ramp rate means extra stress on the rest of the valvetrain.

now the crane cam acutally has more of a slow ramp rate, 62° is a good bit. if i were to build another hyd flat tappet 383 then i would look for a ramp rate in the 50° range. here are a few that i like a bit better than the crane cam, and i certainly like them better than the lunati cam.

COMP Cams 12-212-2 - COMP Cams Magnum Hydraulic Camshafts - Overview - SummitRacing.com
Lunati 00010 - Lunati Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com

this one would probably be my choice, i am a big fan of howards valvetrain products, i have been using them for quite a while with absolutly no problems and their customer service is second to none.

Howards Cams 112141-10 - Howards Cams Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com

and as i mentioned before, i wouldn't go with the scoggin dicky vortec heads for 800.00 when the 180cc RHS pro action heads are the same price and are proven to flow better and flat out perform better.

the Eagle kit you chose is just fine, i've used the 4.030" kit before and it worked great for me. if you match the howards cam, a nice performer rpm intake, a simple holley 750 vac sec carb, cheap HEI distributor (60K volt), with those RHS heads, and a decent set of headers and exhaust then you will be sitting in the 410-425hp rane but the kicker will be the 440-460tq you will make, all while using pump gas.

So how much of a difference would I see in the Howards cam vs the Lunati one I posted? I already have the Lunati, got it for a great deal from another guy. I can always just sell it to someone else and get another cam if it would be that big of a difference though.

Now if I go with those RHS's will I need a different intake than the one I posted? I posted an Edelbrock 7516 performer RPM air gap. But it's designed to fit vortechs. Does that matter?

Also about the distributor, I don't really know anything about picking the right one. You said HEI. But what about trigger style, advance type, or computer control compatible? What should I look for in those areas? And I'm sure the gear material matters, but with that I'd need to know the material of the cam, right?

EDIT: And yes, I'm on a budget. But I'm actually using this summer to build the engine, get the tranny and all the stuff needed for that, and the rear end and all that I need for that. I'm planning on doing the whole swap at either spring of next year or beginning of summer of next year so I can use the whole summer to make sure everything runs right and break it in. So I don't know my full budget yet, but it's definitely enough to get what we've been talking about. But yes, if I could afford heads like AFRs or the like, I'd definitely go that route.

 

[painted jester]

On the stroker's cam profile is important! whether the lift is produced with a low heal (the lowest part of the lobe) or a high toe (the highest part of the lobe) The reason for this is because the rod caps come into close proximity (on longer stroke cranks) with the cam lobes and even hit the lobes on high lift cams and machining is necessary to achieve clearances sometimes negating the use of larger cams! You probably already know this and researched it! But sometimes cams are suggested because of this reason! So I thought Id mention it!:thumbup: In case you didn't know!

Jester

 

[seanphelps321]

On the stroker's cam profile is important! whether the lift is produced with a low heal (the lowest part of the lobe) or a high toe (the highest part of the lobe) The reason for this is because the rod caps come into close proximity (on longer stroke cranks) with the cam lobes and even hit the lobes on high lift cams and machining is necessary to achieve clearances sometimes negating the use of larger cams! You probably already know this and researched it! But sometimes cams are suggested because of this reason! So I thought Id mention it!:thumbup: In case you didn't know!

Jester

Yes. I knew there are a bunch of clearance issues with strokers. I had an idea that there could be cam clearance problems as well. Thanks for reminding me of that. I'll have to keep that in mind.

 

[joelster]

his 92' already has the stronger 7.625" rear in it with the 28 spline axles instead of the 7.5" with the 26 spline axles. you are right about the TQ arm and the control arms. before i started drag racing my current set up i had a 355 putting out about 390-400hp, I upgraded to a 7.625 rearend from a 91' and I never had any issues with it.

think about this, how many LT1 and LS1 camaro's are out there with a set of headers and exhaust, reprogramed, with an aftermarket intake and just some other bolt on mods. these cars are making about 400hp and still using the same 7.625" rearend. dont get me wrong these rearends are week and will likely be the weakest link on the car with 400+hp/tq but i've seen plenty handle this kind of power without any problems.

Not sure where you get this 7.625" information, but both of my LT1 cars came with a 7.5". EVERY LS1 car came with a 7.5 as well. I'm guessing that you are thinking of the oddball Borg-Warner rear that came in a few 3rd gens. Either way both are weak. Possibly with street tires, they will last a long time, but NO WAY at the track or street with a decent drag radial or a sticky DOT tire. Not a chance in hell. My friend grenaded his 10-bolt with a bone-stock LT1 car with a t56 and a set of BFG drag radials.

its the 7.5" rearend with the 26 spline axles which is so much weaker. after saying all this, i must say that with my old set up on my 385, my 7.625" rear didn't last 3 weeks. but it was also putting out 490tq.

They usually snap the teeth off of the ring gear and/or pinion gear when they go. People put a TA Performance girdle on them hoping they will get some life but that is money down the drain.

I am someone who believes saving the money and doing it right the first time so i understand what you are telling him. I just dont think that is what he looking for. for many people 400hp in a street car is all they will ever care to have. based on the parts OP picked, i assumed that he was on a budget that is why i suggested the iron RHS 180 heads, and believe it or not they actually flow 258cfm @ .500", these numbers came from an independant shop that has flow tested hundreds of different heads on their SF600. most $1000-1250.00 alm heads are right in that range with them so how much would that extra $200-450.00 extra for the alm heads acutally benifit him. they are lighter, but if he's not racing then the extra 50lbs will never be seen nor felt. now for the heating aspect. the alm heads will be easier to cool, but as long as he has a decent electric fan he wont have any problems with the irons heads, on my previous motor set up i used Dart 200cc platinum iron heads and i never had any issues with keeping the motor under 190°.

The cooling of the engine is a benefit but the main thing is the ability to up the compression ratio and not detonate. That is something that is FREE that cannot be ignored. Put an iron head on a 383 and run it at 11.5-1 and try to run pump gas. You will have to tune it pig rich and take timing out.

Yes, would a set of AFR 195's, Brodix IK200's, or Dart pro-1 200's along with a hyd roller cam be his best option for making more power, absolutley. with these he would likely make 50-75 more hp all day but he would also spend another $1500.00 doing it.

Sometimes you have to make recomendations based on what you believe the OP wants, not what you would want. :thumbup:

I could piece something together for not much more $$$ and make it much more enjoyable. IMHO vortec heads do not belong on anything over 355 cubes. They simply don't have the ability to feed it correctly. A 355 with a head flowing over 250 will crap all over a 383 on vortec heads. It would cost a lot less too being able to keep the rods, and crank and not needing as much machining. He's going to run a 650 dbl pumper which can support 450+hp, and an Edelbrock Performer RPM intake which can go well over 500hp, and then crutch the build with some tiny heads trying to feed 383 cubes.