twel34

Looking to do an lq4 swap into my 65 LeMans and have a few questions. Car will be a weekend cruiser possibly seeing a few passes a year on a strip. Looking for somewhere around 450 rwhp. There is a possibility that the motor will be stroked out to a 408 but let's say I will keep the stock bottom end for now. Looking at running l92 heads with a somewhat mild cam. Looking at th400 trannys with a transbrake possibly a rossler. So....

Question 1: How difficult is it to get everything to fit under the stock hood?

Question 2: Any opinions on pace performances top end kit- lq4 to l92 carb conversion kit?

Question 3: Can I use the stock accessory drive (looks aside) or will I need to do some relocating?

Question 4: Am I heading in the right general direction? Trying to stay on a fairly tight budget. Any feedback on cam, transmission, ingnition controller, or heads would be greatly appreciated.

I know you guys have probably covered all this info 1000 times and I think I have 13 builds on this site bookmarked. Just looking for some car specific and build specific info.

Thanks!

speedtigger

iTrader: (16)

#1 Was not a problem on my car at all, but I made my own engine mount stands. The tough part is getting it to clear the steering center link and tie rods while the steering is near right and left lock. Make sure you get the right oil pan. I used the Mast HotRod oil pan. It does a good job in these applications.

#2 Not familiar with it. You could post a link.

#3 I did not try the stock truck accessories for the aforementioned appearance reasons. I used Corvette accessories from a 2001. GMPP sells a complete Corvette accessory drive system for about $800.

#4 If you intend to drive the car on the street, I would seriously consider a 4L80E overdrive transmission. I thank all that is good for my OD trans and lock up torque converter every time I drive my car. If you do get an OD trans, I would get a 4.10 or 4.30 gear if you do not plan to run nitrous. For a carb, you can go anywhere from a 750 to a 950 for what you are building. For a cam, you can get a custom cam from several great sponsors of the forum. I have a pretty mild EPS cam (226/234 110+2.5) and it made 440 RWHP on an outdoor dyno on a hot day through a high stall converter. You can see my times in my signature. I think a similar cam would serve you well for the goals that you describe.

twel34

Sorry here is the link.

http://paceperformance.com/i-5146192...n-package.html

speedtigger

iTrader: (16)

That package is not a bad deal when you add up everything you get for sure, but it says that it comes with an Edelbrock ignition controller. You will want the MSD 6010 instead. The Edelbrock controller does not allow for custom ignition timing curves like the MSD does and you will need that for sure. Also, that cam will leave a bit of power on the table and probably will not let you reach your goals. So, you are going to want a custom cam, better valve springs, hardened pushrods and a the MSD ignition controller. So, unless PACE will allow for parts substitutions, I would probably not go that way.

twel34

So here might be a really stupid question, but how large of cam could I run without running into PTV clearance issues with stock pistons? Its my understanding that duration is what causes problems, correct?

speedtigger

iTrader: (16)

It is not a stupid question at all. In my opinion, not enough people ask this question.

It is not actually duration per se either. It is valve timing, or when the valve open and close. So, the answer to the question encompass a whole bunch of information, so it just depends how far into it you want to go. If you look in the stickies in the top of the carbureted section, there is a thread dedicated specifically to this topic. That thread was born out of me asking a very similar question. And, since there was a little info here and a little there, I decided to create a single resource.

To answer your specific question, you are going to have to take a measurement called valve drop. The reason is that I have never seen anyone share this measurement for an LQ4 with L92 heads. Because of the dish in the piston, it is likely to be slightly different than an LS3, so you may have a little more room.

To measure this, merely rotate one cylinder to top dead center, remove the valve springs from the valves on that cylinder and and place some rubber bands on the valve stems to hold the valves in place, install your cylinder head onto your engine with head gasket and slightly snug up a few head bolts just to make sure it is flush. No need to torque. Now, remove the rubber bands and lower the valves until they touch the pistons. Measure how far valve travels from the valve fully closed on the seat to the valve resting on top of the piston. This is best done with a dial gauge, but I have heard of people doing it with a pair of calipers which I am sure is less accurate.

Once you know the "valve drop" measurement for both the intake and exhaust valve, you can estimate how far you can push the cam timing and what valve clearance you could expect.

My valve drop measures .194" on the intake and .204" on the exhaust. Yours will likely be less on the intake due to the large diameter intake valves in l92 heads. On my set up, I can go with something between 230-233 on the intake and as much as 240-246 on the exhaust and still maintain desirable lobe centers for a single plane engine in my RPM range. You will likely be around 227-229 on the intake and about the same or more on the exhaust. This is all assuming that you do not mill your heads which will reduce valve clearance.

Conversely, if you are willing to flycut your pistons, you can pretty much have whatever you want.

Sorry if I went further into it than you wanted to go.

twel34

No not at all! Thanks for lots of good info!

This piston/head combo seems pretty popular so I'm guess I can find some info on what will work and what won't especially after I get the valve drop measured.

Thanks!