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BluePrint 383 or 355 with TPI Finally nailed the tune and my 350 spun a rod bearing because of improper lubrication caused by cylinder wash out from running excessively rich. That said, I am now in the market for a replacement engine. I am looking at BluePrint's 383 here. I have a few questions about going this route. I plan to keep my TPI, at least for a while. My runners are stock bored .05 over to 1.51" I.D. My manifold is ported and polished(not sure if it is bored over). I'll need bigger injectors, TunedPerformance recommends 30-32#'s while southbay suggests 24#'s and I want to confirm which to get. How much will my setup above hinder the 383? I can invest in short runners after install too but I do not think I can for the initial install. Short runners are running 600+ on ebay atm, which while possibly reasonable, given the cost of everything else, I'd rather invest in them at a later date. I could always step down a size to a 355 found here, it is only a little weaker than the 383. Last question, both engines specify they need a weighted late 350 flywheel. I want to make sure I get the right one, but searches for weighted flywheel don't turn anything up that I would feel confident was the right part. I think I have will have a budget of about $6000 and that includes the labor(~18 hours) for my local performance shop to install the longblock and transfer everything over. Opinions, suggestions? Thanks |
Re: BluePrint 383 or 355 with TPI There are SO many variables, but.... Ya gotta decide now what you want later. If you KNOW you're going to replace the intake, buy for that, even if it's not perfect now. If you're not sure......well...you need to make some choices! My opinion, being that you have a 350 now.....go with a 350/355. Tune should be about the same and gets ya right back where ya were. That 383 doesn't suit a TPI at all. Heads and cam are both too big to make it efficient with a TPI. I built my 383/TPI with 180cc heads and a modest cam to all work together, but no doubt I'm giving up power. That 355 has a MUCH better cam for a TPI. Heads are still too big, but it's better matched than the 383. Honestly neither are ideal, Why not have a local machine shop just rebuild you a 355? ....again....if you KNOW you're gonna replace the TPI, then that 383 is a nice engine, but it's too much for a TPI. -My 383 has an extremely, heavily, modified TPI and it still holds it back. I did it because I wanted the look. That is the ONLY reason to not ditch the TPI, especially if you're considering a future upgrade. -My RHS head are only 180cc and with the TPI, my Southbay injectors run at about 70- 75% duty cycle, which is in the green. Ya typically want it at about 80% max. ...those heads are 195cc and with a potential better intake, I might look ...at 36#. Gotta tune for it anyway. Drastically too big of an injector can affect idle and low rpm tuning, but one step bigger shouldn't really hurt. Still....I'd go 350/355. -bored over typically refers to the increase of the cylinder bore. Like a 355 is -bored ".030 over. A manifold isn't really bored, although you could think of porting as the same thing in a way. Increasing the size of the hole!!! LOL. -Flywheel/flexplate would be determined by the crank. I'd call BP and ask them if they can recommend a part number. Bottom line, make a choice on your intake. TPI? Have a local shop build you a 350/355. High performance intake? I still talk to a local shop, but a that 383 is sure a nice looking engine. |
Re: BluePrint 383 or 355 with TPI
Originally Posted by Abubaca
(Post 6271643)
There are SO many variables, but.... Ya gotta decide now what you want later. If you KNOW you're going to replace the intake, buy for that, even if it's not perfect now. If you're not sure......well...you need to make some choices! My opinion, being that you have a 350 now.....go with a 350/355. Tune should be about the same and gets ya right back where ya were. That 383 doesn't suit a TPI at all. Heads and cam are both too big to make it efficient with a TPI. I built my 383/TPI with 180cc heads and a modest cam to all work together, but no doubt I'm giving up power. That 355 has a MUCH better cam for a TPI. Heads are still too big, but it's better matched than the 383. Honestly neither are ideal, Why not have a local machine shop just rebuild you a 355? ....again....if you KNOW you're gonna replace the TPI, then that 383 is a nice engine, but it's too much for a TPI. -My 383 has an extremely, heavily, modified TPI and it still holds it back. I did it because I wanted the look. That is the ONLY reason to not ditch the TPI, especially if you're considering a future upgrade. -My RHS head are only 180cc and with the TPI, my Southbay injectors run at about 70- 75% duty cycle, which is in the green. Ya typically want it at about 80% max. ...those heads are 195cc and with a potential better intake, I might look ...at 36#. Gotta tune for it anyway. Drastically too big of an injector can affect idle and low rpm tuning, but one step bigger shouldn't really hurt. Still....I'd go 350/355. -bored over typically refers to the increase of the cylinder bore. Like a 355 is -bored ".030 over. A manifold isn't really bored, although you could think of porting as the same thing in a way. Increasing the size of the hole!!! LOL. -Flywheel/flexplate would be determined by the crank. I'd call BP and ask them if they can recommend a part number. Bottom line, make a choice on your intake. TPI? Have a local shop build you a 350/355. High performance intake? I still talk to a local shop, but a that 383 is sure a nice looking engine. Thanks |
Re: BluePrint 383 or 355 with TPI 30#hr should be sufficient for 400hp engine. https://www.southbayfuelinjectors.co...o-firebird-tpi |
Re: BluePrint 383 or 355 with TPI Just my opinion, but I would never want a 383 with a 5.7 rod, too much rod angle causes cylinder wear. |
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