Engine SwapEverything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.
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Hello all, long time reader, first time poster, but I finally have a quesition:
I have an 1984 Trans-Am with a non computer controlled carb, 700R4 and a functional cold air hood. I recently purchased Edelbrock TES headers with 3 inch collector, and am upgrading the stock setup 305 to a carbed Vortec headed 350.
1. What Intake should I be using to keep the original hood? I wouldn't mind using the cold air setup (it is pretty rare and still works) so obviously factory clearance is an issue, I want this thing to run quick, but it is a daily driver...
2. I have a mid 80's Ultradyne cam (Yes, Ultradyne...go retro!!) that is brand-new in the box, it is a mild RV cam with about .454 lift and 214 duration. I also have the stock Vortec truck roller cam. Should I use the roller with the 1.6 rockers I happen to have and advance the timing a few degrees on the timing chain? Or keep with an older hydraulic cam for this? I know cam technology has come a long way, but I have no idea what stock cam specks for a vortec truck would be. I do like a little rumble, but hey.. I have the headers now..
3. Any other thoughts? Unfortunately it will be a one wheel peeler for a bit, but that is another project to upgrade the rear end. I have a few carb options, including the factory rebuilt Quad, I have a 600 Edelbrock manual choke and a 600 CFM vac sec Holley from a marine 350 to choose from (I have been collecting parts for a while..)
Thanks guys, I'm planning on handing the heads over to get them checked out within the next few weeks and the motor will be going in early spring!
Edelbrock's regular Performer Vortec, NOT the RPM, should let you keep the cold air thing. I have the same thing on my '84 Trans Am, so I understand about it. I strongly suggest you keep using the truck's roller cam for now, until you're ready to invest in a better hydraulic roller cam. Also, the Vortec heads have very poor exhaust flow compared to their intakes, so a single pattern cam would be a mistake. Since the heads are off, here's your chance to remedy that. If you do, you will find more power. First, do NOT do anything to the intake ports. You'll only goof up an already great thing. I know, I've ruined dozens of Vortec heads back when I had a then-new SuperFlow 1020 flow bench with the wet-flow and swirl attachments. Do get some good stainless valves, 1-piece, swirl-polished, undercut. You can get these for $80 for all 16 from www.competitionproducts.com. I suggest you go for 1.94/1.60", and have the heads worked to accept these larger exhaust valves. Including 30/45/60 degree cuts for the valve job (exhaust only, leave the GM intake valve seats alone) and follow that up with a 75 degree bowl hog. (Exhaust only) Have the shop put a small 30-degree back cut on all of your new stainless valves. Then, IF you're inclined to do more, Get your porting stuff and only do the following: taper the exhaust guides, then quit porting and get the most agressive polishing rolls. On the short side of the rexhaust ports, you'll find a small ridge going across the port. Get rid of that, in all 8 exhaust ports. Then blend the 75 degree cut into the ports, you're trying to create a radius, not remove a lot of iron. Then polish the entire exhaust port, in all 8 holes. Done. Don't do any more. At this point, you could get away with a single pattern cam, but don't use any cam with more than .480" advertised lift. The intake ports stall hard at about 0.475" valve lift.
Thats good to know, the ultradyne cam is a dual pattern, I can get you the specs if that helps but it is a dual pattern mild RV cam, I just wondered how agressive the stock roller would be and if it would have any hot rod noise. I do want this to pull hard up to about 5000RPM limit, traction is always the problem with these cars anyhow..
I have a set of 2.02 and 1.6 valves, you say stick in the exhaust and leave intake, sounds good to me, less work. Just blend the sharp ridges under the valve seats and a parting line, I think I can see those with the valves still in the heads. Keep it light and simple, I'll tell the machinist about your angles and see if he can match that for me!
What should I jet the stock 305 Quad to if I'm keeping it? any experience with that?
Well I was a bit off on the cam, the card states its a SB272/H12 cam (Purchased in 1986) and it is a single pattern 217 duration intake and exhaust with .454 lift on both sides as well. has a lobe seperation of 112 deg..
Vortec truck roller cam is under 200 duration I belive, and LT1 upgrade wouldn't be much hotter. What do you think?
Wow, you have the exact cam running with your setup? That is good to know my friend! Are you running the 700R4? What intake/carb did you choose? Did you modify the exhaust side like was previously recommended here, or run the heads stock? Did you have to mod the exhaust springs to accommodate the extra lift of the 1.6 ratio on the exhaust side? Some people have recommended that as well. Works out to be about .485 lift on the Exhaust with the 1.6 ratio. Tell me more if you have a chance!
Edelbrock's regular Performer Vortec, NOT the RPM, should let you keep the cold air thing. I have the same thing on my '84 Trans Am, so I understand about it. I strongly suggest you keep using the truck's roller cam for now, until you're ready to invest in a better hydraulic roller cam. Also, the Vortec heads have very poor exhaust flow compared to their intakes, so a single pattern cam would be a mistake. Since the heads are off, here's your chance to remedy that. If you do, you will find more power. First, do NOT do anything to the intake ports. You'll only goof up an already great thing. I know, I've ruined dozens of Vortec heads back when I had a then-new SuperFlow 1020 flow bench with the wet-flow and swirl attachments. Do get some good stainless valves, 1-piece, swirl-polished, undercut. You can get these for $80 for all 16 from www.competitionproducts.com. I suggest you go for 1.94/1.60", and have the heads worked to accept these larger exhaust valves. Including 30/45/60 degree cuts for the valve job (exhaust only, leave the GM intake valve seats alone) and follow that up with a 75 degree bowl hog. (Exhaust only) Have the shop put a small 30-degree back cut on all of your new stainless valves. Then, IF you're inclined to do more, Get your porting stuff and only do the following: taper the exhaust guides, then quit porting and get the most agressive polishing rolls. On the short side of the rexhaust ports, you'll find a small ridge going across the port. Get rid of that, in all 8 exhaust ports. Then blend the 75 degree cut into the ports, you're trying to create a radius, not remove a lot of iron. Then polish the entire exhaust port, in all 8 holes. Done. Don't do any more. At this point, you could get away with a single pattern cam, but don't use any cam with more than .480" advertised lift. The intake ports stall hard at about 0.475" valve lift.
Interesting as that's pretty much hwo I ended up working my Vortecs... but it was more out of necessity and that's what i had laying around than anything else.
However, what do you mean about the ports "stalling hard at .475" lift"? Finding performance cams that dont exceed .475" lift is kind of hard. Especially roller cams. Mine is right around there, and it's only a 218/224 at @.050 and that's a pretty tiny cam.
I ask because I was planning on pulling them off next year sometime and getting the valve guides machined down and going with a retro-fit roller setup, and finding a healthy roller cam that doesnt go above .475" is surprisingly hard. Do you think getting a cam that goes to .500 or .525 or so will hurt performance more than it helps? Or is it one of those things where you hit a point of diminishing returns?
Last edited by InfernalVortex; 10-06-2009 at 03:15 AM.
Well I have some questions answered, does anyone else have any opinions on my camshaft situation with reference to the .454 lift 216 duration flat tappet vs a factory truck vortec roller cam? I am leaning flat tappet as I don't have the resources for a $300 cam upgrade right now...
Wow, you have the exact cam running with your setup? That is good to know my friend! Are you running the 700R4? What intake/carb did you choose? Did you modify the exhaust side like was previously recommended here, or run the heads stock? Did you have to mod the exhaust springs to accommodate the extra lift of the 1.6 ratio on the exhaust side? Some people have recommended that as well. Works out to be about .485 lift on the Exhaust with the 1.6 ratio. Tell me more if you have a chance!
Thanks!
Yep, in my 86 TA with the 355. I have a performer intake since it is all i had laying around. A RPM air gap is on the to do list. It has a 700R4 but it needs a stall BAD(will be here at the end of the week), has a holley 750 vacuum secondary i built myself. I studded and used guide plates and had them modded to accept over 500 lift, but i didnt get a chance to port them at all like i wanted.
It is .480 on the intake and .512 on the exhaust side with the 1.6 on the exhaust.
Screams to 6200 RPM or so with shorty headers and the BS intake. Trapped 81 MPH in the 1/8th mile with a 2.2 60 ft, no stall and gay 3.07 gears.
Swapping the stall in soon and i hope to have a 3.23 or better rear in my next week too.
